IFW Research Program



On the track of the unexplored

The IFW research program brings together the disciplines, methods and competences of the five IFW institutes. Despite its breadth and interdisciplinarity, all IFW research activities have in common that scientists are investigating still unresearched properties of matter with the aim of developing new functionalities and applications.

Three pillars of the triangle

Quantum Materials
... are solids showing peculiar quantum phenomena promissing for application.

Functional Materials
... are solids performing specific functions based on their physical and chemical properties.

Nanoscale Materials
... are substances and structures, of which a single unit in one or more dimensions is sized below 100 nanometers. 

 

Research Area 3:Quantum effects at the nanoscaleResearch Area 2:Functional through sizeResearch Area 1:Functional quantum materialsResearch Area 4:Towards productsQuantumMaterialsNanoscaleMaterialsFunctionalMaterials

Four Research Areas - 13 Subdivisions

The junction of the three fields  Quantum – Nano – Function is the unique feature of the IFW. Along the junctions of these fields we have defined four research areas where we cover the range from fundamentals to functionalities in a stragegic manner. These are grouped into 13 subdivisions.

Subdivision 1: Exotic ground states and low-energy exitations in bulk systems

Fundamental experimental and theoretical research of complex bulk materials with strong electron-electron correlations and entanglement of spin, charge, orbital and lattice degrees of freedom, their novel quantum magnetic phases and exotic excitations.

Transition metal (TM) and rare earth (RE) compounds may provide experimental realizations of various fundamental but also more exotic models of quantum magnetism. We are investigating novel phenomena which result from low-dimensionality, magnetic frustration and spin-orbit coupling (SOC) being decisive in defining the ground state. Such systems are often characterized by strong fluctuations, lack of (long-range) magnetic order, a high degeneracy of states, and may bear fractionalized or even topological excitations. In order to obtain new fundamental insights into these correlated states of quantum matter, we employ IFW’s unique combination of relevant mutually complementary methods and expertise. This comprises material synthesis and crystal growth, transport, magnetic and thermodynamic characterization, various spectroscopic (ARPES, STM/STS) and dynamic local spin probe (ESR, NMR) techniques, electronic-structure calculations and various approaches to treating effective many-body models.

Originally, great attention in this research topic has been paid to the  investigation of quantum ground states and elementary excitations in insulating 3d TM compounds with low-dimensional and/or frustrated spin networks as found in “classical” paradigm materials, e.g., in cuprates, manganites, and cobaltites, as well as of complex magnetic properties of intermetallic Heusler compounds.

Recent discoveries of new fundamental phenomena driven by strong SOC, such as novel Mott-like insulating phases in 4d and 5d TM compounds and topologically nontrivial phases in semiconductors, have opened exciting challenges and opportunities for the exploration of new magnetic effects in these emerging materials and therefore have naturally become an important subject of our research since a few years. This strategic development has enabled to position our research as an important part of the DFG-funded Collaborative Research Center 1143 “Correlated Magnetism: From Frustration To Topology” coordinated by the TU Dresden and to further enhance national and international visibility of the studies of emerging magnetic quantum matter at the IFW Dresden.

Involved groups at IFW: IFF and ITF, namely Kataev, Wolter-Giraud, Hozoi, Janson

Subdivision 2: Unconventional Superconductivity: Mechanisms, materials & applications

Fundamental research on properties of unconventional superconductors; Materials and device development for application

Fundamental research is devoted to the interplay of the superconducting phase with potentially competing phases of electronic and magnetic order as well as connected fluctuations, role of nematic order and fluctuations for the understanding of superconductivity. The research benefits from the unique combination of relevant mutually complementary methods and expertise at IFW. This comprises material synthesis and crystal growth, epitaxial film growth, transport, magnetic and thermodynamic characterization, various spectroscopic (ARPES, STM/STS) and dynamic local spin probe (ESR, NMR,NQR) techniques, some of these methods used in combination with strain, electronic-structure calculations and various approaches to treating effective many-body models.

Our research towards the application of unconventional superconductors included the improvement of the respective materials itself and the development of devices based on these materials.

Involved groups at IFW: IFF, IMW, ITF namely Borisenko, Hess, Charnukha, Koepernik, Hühne

 

Subdivision 3: Magnetic materials for energy / Materials for energy storage

Tailoring magnetic intermetallic alloys and compounds towards energy applications; Electrochemical and structural studies on materials and devices for energy storage

Magnetic intermetallic alloys and compounds exhibit diverse physical states which are characterized, e.g., by the size and direction of the atomic moments, their correlation in space and time, their mutual and spin-lattice interaction energies. The related properties and phenomena (spontaneous magnetization and order, magnetic anisotropy, spin polarization at the Fermi energy, phase transitions, thermomagnetic, magnetocaloric, and magneto-transport effects) enable these materials to be used in energy-efficient applications. Relevant applications comprise permanent magnets for electric motors and generators, magnetic information storage and magneto-resistive sensors. Emerging topics include multicaloric cooling, and thermomagnetic energy conversion. The magnetic properties and functionalities of intermetallic materials are governed not only by their intrinsic properties (electronic structure, atomic moments, magnetic anisotropy, and ordering temperature), but to a large extent by extrinsic contributions (segregation, crystallographic texture, phase distribution) and by their dimensionality. Hence, identifying, understanding, and controlling these contributions are the key to tailoring magnetic intermetallics towards energy applications.

A second branch in this subdivision is devoted to novel materials, devices and concepts for energy storage. It covers fundamental electrochemical and structural studies of charge or discharge mechanisms as well as the development of small scale lab-on-chip device and materials for large scale storage. The material development is supported by density functional calculations on working electrochemical potential, crystal and electronic structure.

Involved groups at IFW: IFF, IMW, IKM, ITF namely Wurmehl, Krautz, Fähler, Woodcock, Poccia, Richter

Subdivision 4: Engineering magnetic microtextures

Creation, understanding and control of patterns in magnetically ordered materials, including domain walls and skyrmions; Advanced in situ Kerr Microscopy, Magnetic Force Microscopy and Transmission Electron Microscopy

Patterns in magnetically ordered materials, also known as magnetic microstructures and -textures, are vital for their functionality. Creation, understanding and control of such patterns, including domain walls and skyrmions, in variable geometries allows to use materials as switchable units in devices. The aim of this topic is the fabrication of non-collinear states on nano- and mesoscales (up to several µm), which will be stable at room temperature and which can be integrated in various devices. Main challenges are (i) the design and fabrication of material systems with appropriate magnetic couplings and high transition temperatures, and (ii) the development of versatile microscopy methods to investigate their properties. We employ state-of-the-art deposition methods to synthesize suitable magnetic film systems as well as various magnetic imaging techniques such as Magneto Optical Kerr microscopy (MOKE), Magnetic Force Microscopy (MFM), and Transmission Electron Microscopy based techniques.

New directions in the search for suitable materials focus on ferrimagnets and antiferromagnets, where the complex spin-structure and intrinsic frustration may generate novel chiral and topological textures. For chiral and centrosymmetric ferromagnets, textures are induced and controlled through strain engineering, curvilinear arbitrary shapes of magnetic specimens or through magneto-ionic manipulation on patterned surfaces. Magneto-ionic manipulation of magnetic metal oxide/metal films at critical points is explored to obtain voltage-reprogrammable magnetic domain patterns. Micromagnetic continuum theory and DFT calculations are used to model these various materials, and to unravel the counteracting influence of dipolar stray-field effects and chiral antisymmetric Dzyaloshinskii-Moriya exchange on magnetic textures. New developments in magnetic imaging address electron holographic and tomographic methods for curved nanoobjects, deconvolution techniques to increase the resolution of Kerr microscopy and magneto-optical methods based on linear dichroism (Voigt effect) to investigate materials for antiferromagnetic spintronics. Advanced in-situ Kerr microscopy of electrolyte gated metal oxide/metal films is conducted to resolve the impact of magneto-ionic manipulation on magnetic domains.

Involved groups at IFW: IFF, IMW, IIN, ITF namely Schäfer, Leistner, Thomas, Rößler, Karnaushenko, Mühl, Lubk

Subdivision 5: Solidification, non-equilibrium phases / High strength and biocompatible alloys

Metallic glasses and nanostructured composites, shape memory alloys, high-entropy alloys, high performance steels and Ti- and Al-based alloys and composites for structural applications, Ti- and Fe-based alloys for implants

The research of this subdivision is driven by continuously increasing demand for high-performance materials for engineering and medical applications. Due to formation of compositionally, structurally or morphologically metastable phases and microstructures by processing under non-equilibrium conditions, advanced materials with tailored mechanical, physical and bio-chemical properties with prospect of emergent applications can be synthesized. The development of new materials also aims at combining unrivalled properties that are otherwise mutually exclusive by fabrication under equilibrium conditions.

Metallic glasses and nanostructured composites, shape memory alloys, high-entropy alloys, high performance steels and light weight/ high strength Ti- and Al-based alloys and composites for structural applications, Ti- and Fe-based alloys for load-bearing bone implants and vascular implants are in the scope of the research. The fabrication and processing techniques include casting and powder metallurgy, rapid solidification, additive manufacturing, thermoplastic shaping, thermal treatment, cold working, and chemical and thermomechanical surface modifications. Along with standard methods, new characterisation techniques are being developed in collaboration with IFW Research Technology Department, DESY and ESRF. Studies of non-equilibrium solidification processes are performed on the ground and under microgravity conditions.

Involved groups at IFW: IKM namely Hufenbach, Kühn, Gebert, Freudenberger, Calin, Scudino

Subdivision 6: Multifunctional inorganic nanomembranes / Flexmag

3D rolled-up nanomembranes and devices, nanomembranes for energy storage, rolled-up microelectronic devices, Optoplasmonic and photonic microcavities.

Nanomembranes are thin, flexible, transferable and can be shaped into almost arbitrary 3D microarchitectures. The ability to create nanomembranes out of virtually any material and material combination with a plethora of different thin film deposition techniques such as thermal evaporation, sputtering, chemical vapor and atomic layer deposition brings about a wealth of new functionalities and has generated worldwide impact in several application fields. On one hand these rely on nanomembranes targeting large area electronic applications, which the IFW has previously pioneered for flexible and stretchable magnetoelectronics, composite materials for microbattery applications as well as GMR pastes/inks for printable electronics. On the other hand differentially strained nanomembranes are exploited for NEMS and MEMS origami structures, in particular for compact on and off chip rolled-up microtube architectures towards which the IFW has made decisive contributions already in the very early days of this emerging research field. In this context, 3D rolled-up nanomembrane devices include microelectronic, RF, GMR and biomimetic microelectronic components for biomedical applications, 3D scaffolds for in-depth single cell investigations, ultrasensitive biomedical sensors and photonic and optoplasmonic microcavities. Most of these subtopics are finely interwoven with research topics found in research areas one, three and four.

Flexible magnetoelectronics: The most intriguing progress is based on the concept of imperceptible electronics, which was adopted for GMR sensing using active electronics. This work is expected to have profound impact in applications such as touchless human–machine interaction, motion and displacement sensorics for soft robots or functional medical implants, as well as magnetic functionalities (e.g. navigation and orientation) for epidermal electronics.

Nanomembranes for energy storage: Three-dimensional and two-dimensional hybrid nanomembranes fabricated by thin-film deposition exhibit impressive electrochemical performance and are ideal candidates to power lithium ion batteries, fuel cells and capacitor applications. Hybrid nanomembranes improve the conductivity and also facilitate ultra-high rate capability, long-term cycling performance, and excellent Coulombic efficiency.

Rolled-up microelectronic devices: Arrays of RF devices such as antennas, coils, resonators and transformers can be produced over large areas with a yield of more than 90% in a highly parallel 6” wafer scale self-assembly process. Other proof-of principle devices include 3D magnetic field vector angular decoders, helical superconducting microwave detectors and thermoelectric harvestors.

Optoplasmonic and photonic microcavities: Microtubular nanomembrane cavities support optical whispering-gallery mode resonances which are capable of interacting with surface plasmons in specially designed opto-plasmonic microcavities. The coupling of resonant light and surface plasmons results in the formation of hybrid photon-plasmon modes in metal layer coated optical microcavities. This work provides a universal picture for understanding the basic physical mechanisms of photon-plasmon mode coupling in metal-coated microcavities, and as such is relevant for both fundamental and applied studies in photonics and plasmonics.

Involved groups at IFW: IIN, IKM, IFF, ITF namely Karnaushenko, Hufenbach, Lubk, Grafe, Rößler

 

Subdivision 7: Micromotors and drug delivery

Development of biocompatible microbots to perform medical tasks at the microscale like cell transport or targeted drug delivery

Several concepts have been pursued by different research groups worldwide to realize propulsion on a small size scale, where viscous drag dominates over the inertial forces. Potential geometries for future carriers at the microscale range from tubular microjets and Janus particles or rods over bio-inspired artificial flagella and cilia to helical micromotors. Over the last 11 years, IIN-IFW has pioneered the fabrication and functionality of powerful bubble-propelled micromotors, which by now are employed by several groups worldwide to achieve biomedical and environmental tasks on the microscopic scale. A biocompatible alternative towards microrobotic motion is to rely on the external power supply such as magnetic fields which are not harmful to the human body. For instance, a small magnetic microhelix that rotates around its long axis by following the rotation of an applied magnetic field, results in an efficient forward movement through viscous fluids, like a screw propeller. Hybrid micro-biorobots which are driven by powerful microorganisms (e.g. bacteria) or motile cells (e.g. sperm cells) are also a promising approach as they combine the advantage of biological components to the functionality of engineered microparts. Eventually, this research topic aims to develop biocompatible microbots to perform medical tasks at the microscale, for example to perform micromanipulation, cell transport, or drug delivery.

Different contributions from our Institute have been achieved in recent years, ranging from self-propelled catalytic micromotors, magnetically guided micromotors, microengines with energy on-board to trigger the micromotor motion speed and perform micromanipulation tasks, to sperm-hybrid microbots, in particular studying their motion in realistic fluids to optimize their cap design, or for targeted drug delivery. For any in-vivo application, the microrobots need to be motion-controlled to achieve a meaningful task inside the body. We have recently demonstrated real-time tracking of single microrobots in deep tissue by optoacoustic imaging and optical reflection techniques bringing the whole research field to a decisive step closer to clinical applications. The IFW will organize the “First Leibniz-Nature Conference on Microrobots and Nanorobots for biotechnology” in Dresden in June 2020. The pioneering work of the IFW in this research topic has been appreciated by two ERC grants recently awarded to Mariana Medina-Sánchez and Oliver G. Schmidt.

Involved groups at IFW: IIN namely Oliver G. Schmidt and Mariana Medina-Sanchez

Subdivision 8: Thermoelectric materials

Experimental studies of transport properties of thermoelectric materials, bulk materials development and applications-based engineering of lab-scale thermoelectric devices

Thermoelectric energy converters are attractive for application in waste heat recovery technologies. Peltier coolers are also a vital part of modern thermal management systems. However, the comparatively low efficiency reached by the current state of the art thermoelectric materials hinders the broad-scale expansion of high-performance thermoelectric device implementation. To increase the efficiency of thermoelectric materials through tailored engineering, a deep understanding of the interlinked electron and phonon transport properties in nanostructured materials is a prerequisite. Challenges remain on how to efficiently decouple both the electrical conductivity and thermal conductivity, as well as how to increase the stability of the thermoelectric material and the compatibility with environmental requirements. The fabrication of thermoelectric devices, especially microdevices, presents further challenges. One key challenges is how to embed the optimized high-performance thermoelectric materials into a device with technology that is compatible with the prospective application.

In this research, we combine (i) knowledge-driven experimental studies of transport properties with (ii) nanograined bulk materials optimization and (iii) applications-based engineering of laboratory-scale devices. The research activities hereby comprise:

  1. the development of a platform for the characterization of thermoelectric transport properties using single-crystalline microribbons obtained by focused ion beam cutting
  2. the development of high power factor and sustainable thermoelectric bulk materials for mid-to-high temperature thermoelectric energy conversion
  3. the fabrication and functional integration of fully operational microenergy harvesting and microthermal management devices with long-term reliability and cycling stability

The IFW’s activities in this subdivision are characterized by the combination of material development with internationally recognized microdevice fabrication. These activities notably include the fabrication and characterization of microthermoelectric devices that are indicated to be stable long-term and highly reliable, which can only be performed in a select few laboratories globally. We further use the expertise developed here in fabrication technology for knowledge-driven experimental studies using microribbons that were obtained by focused ion beam cutting, which offers a unique approach to the acquisition of high-quality thermoelectric transport data and, in turn, stimulates new interpretation of transport phenomena.

Involved groups at IFW: IMW Schierning

Subdivision 9: Surface acoustic waves: Concepts, materials & applications

Concept development for new surface acoustic wave (SAW) systems, investigation of advanced SAW material systems, microacoustic devices for microfluidic actuators, temperature sensors and wireless interrogation

Surface acoustic waves (SAWs) provide a versatile base for emerging applications including sensors operating under harsh conditions and actuators in fluidic environments. Our research is consequently focused on future‐oriented fields of SAW application comprising the following main aspects:   Concepts: Innovative concepts for new system designs are developed based on precise analysis and thorough physical modeling of wave excitation, propagation and interaction effects, including such of higher order.   Materials: The investigation of advanced SAW material systems - especially for devices working under high temperature or with high power-durability - comprises (i) piezoelectric crystals and films, (ii) thin film electrode systems, and (iii) strategies for interface engineering. This includes high-precision microacoustic characterization of new crystals and high-efficiency piezoelectrics in a wide temperature range in order to obtain complete material data sets for simulation and design of high quality SAW devices. Furthermore, material routes for highly stressable and purpose-compatible thin film electrode systems on different piezoelectric substrates, with properties adapted to harsh operation conditions and fluidic/biological environments, are investigated. This comprehension of functional interlayers/barriers requires also improvement of methods for surface and interface analysis.   Applications: Microacoustic devices addressing new fields of application in microfluidic actuators, e.g. acoustic tweezers or fluid atomizers, as well as in temperature sensors for harsh environment and wireless interrogation are investigated.

Involved groups at IFW: IFF, IKM namely H. Schmidt, Winkler

Subdivision 10: 2D Systems / Designed interfaces and heterostructures

Correlated and magnetic van-der-Waals like systems (RuCl3, CrI3 and VSe2); Transport properties across magnetic heterointerfaces; Growth, spectroscopic characterization & theoretical modeling

The cross-over from bulk-like materials to thin films or monolayers (MLs) is one route towards new quantum effects in materials. These phenomena might be observed in either free-standing objects or at heterointerfaces. Notable examples are the occurrence of a 2D electron gas at the LAO/STO interface. More recently, a strongly enhanced photoluminescence was observed in MLs of semiconducting group-VI transition-metal dichalcogenides (TMDCs) such as MoS2. These two examples also demonstrate the archetypical approaches to reach the 2D limit: either in a bottom-up fashion via dedicated growth methods or via top-down approaches such as exfoliation. In particular, exfoliation is the method of choice for van-der-Waals systems such as TMDCs and black phosphorus among others.

The activities on these ML materials have been strongly focused on non-correlated and non-magnetic compounds. These materials are supposed to replace graphene by a system that is intrinsically semiconducting. Recently, correlated and magnetic van-der-Waals like systems, e.g. RuCl3, CrI3 and VSe2 have attracted much attention and hold great promises to augment the number of presently available 2D materials. Thickness dependent magnetism has been already demonstrated down to the monolayer for CrI3 and VSe2 and might steer intense research effort because of possible applications in nano-storage devices. But the ground state of correlated materials in the 2D limit could also support exotic properties yet to be discovered.

Research on this new topic within IFW's research program spans a broad range of IFW's core competences: from growth techniques such as atomic layer deposition, molecular beam epitaxy (ALD, MBE) over spectroscopic characterizations (photoluminescence, photoemission) up to dedicated theoretical modeling employing quantum chemistry and density-functional based calculations. In addition, the transport properties across magnetic heterointerfaces are of fundamental as well as practical importance. Here, we focus on thermal and electrical transport and look into, e.g., spin transport across interfaces. Of particular interest are new curvature-induced properties, e.g. two-dimensional topological solitons in curvilinear magnetic films.

Involved groups at IFW: IFF, ITF, IKM namely Schäfer, Leistner, Thomas, Rößler, Karnaushenko, Mühl, Lubk

Subdivision 11: Quantum and nano-photonics

Preparation of semiconductor quantum dots, topological photonic rings, opto-plasmonic cavities and nanoparticle polymers for the investigations of single and entangled photons, propagating surface plasmon polaritons and localized surface plasmon resonance

The design and fabrication of photonic nanostructures provide new opportunities for studying fundamental phenomena of quantum and nano-photonics and realizing novel photonic devices such as nanoantennas or metamaterials by control of light at the nanoscale. The careful preparation of semiconductor quantum dots, topological photonic rings, opto-plasmonic cavities, and nanoparticle polymers allow for the investigations of single and entangled photons, propagating surface plasmon polaritons and localized surface plasmon (LSP) resonances, which are the focus of this research topic. That particularly includes the generation of high quality entangled photon pairs from carefully designed III-V quantum dots, of optical Berry phases acquired through spin-orbit interacting light in microcavities, of hybridized LSPs on rationally designed nanoparticle assemblies, and of magnetic LSPs on topologically insulating plasmonic structures. We develop and employ technologies and expertise available at the IFW-Dresden –– ranging from photonic nanostructure synthesis (MBE growth, electron beam lithography, post-etching, Rolled-up nanotech) to various characterization methods (by confocal microscopy, photon correlation measurements, Electron Energy Loss Spectroscopy (EELS)), and further supported by theoretical calculations –– using finite element method (FEM), finite-difference time-domain (FDTD), or boundary element method (BEM) etc. –– to obtain new fundamental insights into quantum and nano-photonics and explore practical applications for the coming era of quantum information in science and technology.  

Involved groups at IFW: Ma, Lubk, Charnukha

Subdivision 12: Functional molecular nanostructures and interfaces

Fullerenes and Carbon nanotubes with new functionalities; Charge and spin transfer at novel organic heterointerfaces; Novel nanoscale organic/hybrid functional devices like molecular rectifier, spin valves, thin-film field-effect transistors

Molecules and molecular solids characterized by π-derived electronic states are in the focus of research activities world-wide. For instance, they support semiconducting behavior and associated particular optical properties in the visible regime. Therefore many π-conjugated molecules are already applied in organic electronic devices, a field that is still rapidly developing. As a consequence, functional interfaces based upon organic molecular materials play an important role. Moreover, the π-conjugated electronic states are also responsible for the structure and the stability of purely carbon-based nanostructures, the fullerenes. One of the very attractive and fascinating properties of the latter is the possibility to use them as containers for other species, as they are distinguished by their hollow interior. One of the key issues in regard of the understanding and in particular the functionalities of carbon-based molecular nanostructures as well as of interfaces involving π-conjugated molecular species is the thorough and comprehensive understanding of charge transfer processes to the respective molecular material and the nature of charged states of the molecules themselves, either on their own or at interfaces.

It is one central aim within this research topic to investigate these charge transfer processes and states of selected molecular nanostructures and interfaces using state-of-the-art, complementary techniques. This will allow us to determine many relevant parameters and properties and thus provide a comprehensive knowledge of these issues. The combination of techniques available in the IFW Dresden is quite unique, also on an international level. Furthermore, the research groups involved in this research topic have a long-standing and internationally visible expertise in the development and application of their methods as well as in the investigation of electronic and optical properties, charge transfer and charged states of functional molecular materials with π-conjugated electron systems.

In addition we will implement straight on our knowledge about carbon nanotube (CNT) to industrial applications. Herein carbon nanotube yarns (CNY) are novel carbonaceous material transferring the well-known outstanding properties from nano (CNT) to the micro scale (CNY). CNY are very promising candidates for industrial applications due to their high heat conductivity, electrical conductivity, and mechanical strength combined with a very good handling of a micro-material.

Involved groups at IFW: Knupfer, Popow, Dmitrieva, Krupskaya, Gemming, Richter,  Zhu

Subdivision 13: Topological states of matter

Theory: prediction of new topological phases; Materials design: synthesis of photonic lattices, novel bulk single crystals, nanowires, thin films; Experimental physics: spectroscopic and transport properties

Probing unconventional topology is one of the most extensively investigated research fields of the last decade, both in experimental as well as theoretical condensed matter physics. Recently, many new directions have emerged within the topological class of materials, for example topological crystalline insulators, fractional topological insulators, topological photonic crystals, topological metals, Dirac- and Weyl semimetals including type-II materials and those possessing multiply degenerate Dirac and Weyl points with higher topological charge. This diversity and richness of topological states and phases is a broad source of inspiration for our research. Our strategy for probing specific topological matter of electrons and photons is 3-fold and entangles cutting edge theory, materials design and synthesis as well as targeted experiments. More specifically, this entails i) the prediction of new topological phases of electronic matter and photonic lattices as well as electromagnetic manifestations and implications of topology, ii) the design and synthesis of photonic lattices, novel bulk single crystals, nanowires, thin films as well as pertinent functional heterostructures, and iii) experimentally probing the systems’ topological nature by scrutinizing their spectroscopic and transport properties.

Involved groups at IFW: Isaeva, Lubk, Dufouleur, Hess, Borisenko, Thomas, Nogueira, Fulga, Ma

List of publications


	surface of a chip, violet illuminated in dark surroundling

Research Area 1

Functional quantum materials

Bulk materials with a potential functionality due to novel, unconventional electronic properties

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	micro-antenna made from flexible nanomembranes

Research Area 2

Function through size

Material properties arising from structural arrangements at the nanoscale, e.g. nanomembranes or nanostructured alloys

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	close look into a high vacuum chamber with complex device for smple movement and positioning

Research Area 3

Quantum effects at the nanoscale

New concepts and ideas for electronic or photonic devices based on quantum physics

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	a chip on a one cent coin

Research Area 4

Towards products

Targeted application oriented research. Research projects that are close to prototypes and products.

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Research Area 1

Functional quantum materials

Research area 1 is focused on bulk materials in which a potential for applications emerges from their complex, quantum mechanical electronic properties. These electronic properties can

  • result from a complex interplay and ordering of electronic spin, orbital, charge and lattice degrees of freedom,
  • emerge in a more general sense from the presence of strong electronic correlations,
  • appear through competing or strongly frustrated magnetic interactions, or
  • be observed in the context of topologically protected spin and charge states.

These physical material's properties manifest themselves in a number of material classes: in certain families of transition-metal oxides, in molecular solids and in a range of intermetallic materials. What sets these systems apart is that their valence and conduction electrons typically retain to some extend their atomic character, resulting in a rich interplay of localised and delocalised electronic degrees of freedom. This renders these materials both practically and conceptually very different from simple metals and semiconductors with well-understood itinerant quasi-particles. Often the quantum mechanical interplay between the localised and delocalised electronic degrees of freedom leads to anomalous charge transport properties, for instance due to the presence of metal-insulator transitions, and exceptional types of ordering phenomena, such as unconventional forms of superconductivity and quantum magnetism. Functionalities that arise from this are for instance large magnetocaloric effects, high temperature superconductivity, magnetism with very strong anisotropy and colossal/giant magnetoresistance.

Research Topics in Research Area 1 "Functional Quantum Materials"

1.1          Exotic ground states and low-energy excitations in bulk systems
1.2          Unconventional superconductivity: Mechanisms, materials & applications
1.3          Magnetic materials for energy
1.4          Engineering magnetic microtextures

 

Research Area 2

Function through size

The functionality of a material decisively depends on size and interfaces, and this in turn defines the application area the material will be used for. The research area relies on the expertise of an interdisciplinary team of materials and electrical engineers, physicists and chemists and deals with the unique mechanical and functional properties of materials as they or their constituents change from macro-, to micro- and nanoscopic sizes. Activities cover bulk functional materials with potential applications as light weight structural components and high strength tools as well as elastic nanomembrane materials which will be exploited in conceptually new generations of flexible and compact on- and off-chip devices. Shape, size and interfaces also determine the fundamental properties of nanomagnets, which may find use in magnetic probes and data storage elements. We also address the improvement of new thermoelectric materials, e.g. special alloys, and the various capabilities of nanostructuring show enhanced efficiency and promise new applications. All research efforts are cross-linked by common methodological approaches and interests, which shed light on the structure, chemical composition and physical properties of materials at different length scales.

Research Topics in Research Area 2 "Function through size"

2.1          Solidification and non-equilibrium phases
2.2          Multifunctional inorganic nanomembranes
2.3          Micromotors & drug delivery
2.4          Thermoelectric materials

 

Research Area 3

Quantum effects at the nanoscale

In this Research Area we address materials and structures with quantum mechanical effects that are due to their nanoscale. These are very thin films, surfaces and interfaces, so called heterostructures formed by thin films of different composition, quantum dots, photonic crystals and molecular nanostructures like fullerenes, conducting polymers and organic semiconductors.
In the field of nanophotonic the research work at IFW aims to explore several long-standing questions and challenges. Our work approaches fundamental topics: such as the generation of single photons and entangled photon pairs with semiconductor nanomaterials, the strong light-matter interactions in the quantum regime.  More applied questions concern the fabrication of advanced photonic devices such as quantum light emitting diodes, rolled-up optical microcavities and 3D photonic crystals. When combined together, this multifaceted research could enable the realization of complex photonic functionalities with an integrated opto-electronic platform.
At the nanoscale also entirely new physical properties may emerge, for instance at surfaces and interfaces of topological insulators where the spin of surface electrons is locked to their momentum, a property that is interesting in the context of spintronics. Work at the IFW Dresden in this area is a nice example of a very interdisciplinary research effort, combining the available experimental and theoretical expertise to investigate topologically protected surface states and transport properties, again combining synthesis, theory and experiment.

Research Topics in Research Area 3 "Quantum effects at the nanoscale"

3.1          2D Systems and heterointerfaces
3.2          Quantum and nano-photonics
3.3          Functional molecular nanostructures and interfaces
3.4          Topological states of matter

Research Area 4

Towards Products

This research area comprises materials whose physical, mechanical and chemical properties are to be optimized with respect to certain applications, prototypes and products. Usually this is achieved in close cooperation with partners from industry. In the case that scientific results are of economic importance intellectual property rights are secured. A large number of national and international patents and a high degree of licensing indicate their practical relevance .
A typical example are surface acoustic waves components. These are used in sensors and as frequency filters for the channel selection in signal transition. They consist of a piezo-electric single crystal chip which transforms electric signals in acoustic ones and back. The IFW has contributed a number of innovations in this field, for example a considerable improvement of temperature stability and of electromechanical excitation by a special thin film material.
Further projects in this research area concern materials for bio-medical applications, alloys for high-strength materials, nanomembranes for flexible electronic devices and demonstrators for the application of high-temperature superconductors.

Research Topics in Research Area 4 "Towards products"

4.1          Surface acoustic waves: Concepts, materials & applications
4.2          Materials for energy storage
4.3          High strength and biocompatible alloys
4.4          FlexMag: Development centre for flexible magnetoelectronic devices
4.5          Concepts and materials for superconducting applications

Quantum Materials

Quantum materials are solids showing peculiar quantum phenomena related to unconventional spin interactions, electronic correlations, electron-photon interactions and/or topological bandstructures. Examples are superconductivity and magnetism. Quantum effects have also a strong influence in materials with spatial extension constraint to the nanometer scale, like nanoparticles, thin films or nanotubes.

Functional Materials

Functional materials exhibit special physical, mechanical or chemical properties which enable them to fulfil a specific function in devices, e.g. conducting electric current, filter acoustic waves of a certain frequency, shielding magnetic fields or storing energy.

Nanoscale Materials

Nanoscale materials are solids or structures whose length scale comes in one or more dimensions to 100 nanometers or less. This can change their physical and chemical properties a lot and opens up space for new functionalities. In this context molecular nanostructures, inorganic nanomembranes, nanoparticles, nanocrystalline alloys and lithographically prepared nanostructures are studied at the IFW Dresden.