Research highlights and news

Magnetic Weyl Semimetal

Angle-resolved photoemission directly reveals two pairs of Weyl points connected by the Fermi arcs in the canted antiferromagnet YbMnBi2.

Nat. Commun. 10, 3424 (2019)

Molecular magnets

Strong magnetic interactions inLn2@C80(CH2Ph) with huge coercivity through a redox-active metal-metal bond

Nat. Commun. 10, 571

Ultrarelativistic Kane plasmon-polaritons

Access and control of nonequilibrium large-momentum plasmon-polaritons in Hg0.81Cd0.19Te thin films using light sources in the standard telecommunications fiber-optics window

Science Advances 5, eaau9956

New antiferromagnetic topological insulator

Manganese bismuth telluride heralds a new, post-doping era in the field of magnetic topological insulators

Nature 576, 416 (2019)

Research at IFF

At the Institute for Solid State Research (German: Institut für Festkörperforschung , in short IFF) we host under one roof  the synthesis and crystal growth of novel quantum- and nano-materials,  a wide portfolio of experimental techniques that help us understand their physical properties, and the exploration of their potential for applications in fields from electronics to medicine. An important aspect of our work is the continuous improvement and development of experimental techniques.

Research topics

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Facilities

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Recent Publications

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Habilitations, PhD Theses, Masters and Bachelor Theses

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Research Topics at IFF

In quantum materials potential functionalities for technological applications emerge from their complex, quantum mechanical electronic properties. Such complex electronic properties may result from the interplay and unusual ordering phenomena of electronic spin, orbital and charge degrees of freedom and can be observed in the context of topologically protected spin or charge states or for particular geometries.

Material classes include certain families of transition-metal oxides, molecular solids and a range of intermetallic materials. What sets these systems apart is that their valence and conduction electrons typically retain to some extent their atomic character, resulting in a rich interplay of localized and delocalized 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 localized and delocalized 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.      

The plethora of spectacular and surprising phenomena that can occur in quantum materials poses one of the greatest set of challenges for cutting-edge experimental and theoretical condensed matter physics. As a rule material-specific predictions for the occurrence of many of these phenomena are very difficult, even if some of the presently booming research topics in this field, for instance the investigation of magnetic skyrmions and new topological states of matter, have emerged from a strong theoretical research effort and remain being strongly pushed by it.

When the dimensions of materials are restricted to the nanometer length-scale, new electronic properties emerge. This is related to the fact that any macroscopic object, when scaled down to a nanometer-scale, starts exhibiting distinct quantum mechanical properties. However, at the nanoscale also entirely new physical properties may emerge, for instance at surfaces and interfaces of topological insulators (TIs) where the spin of surface electrons is locked to their momentum, a property that is interesting in the context of spintronics.

The technological ability to engineer and shape materials at the nanoscale opens up a very well-defined road to control the materials properties and functionality in a systematic manner. It requires the synthesis, modelling and structuring of nanosystems, which is pursued in the context of a broad span of nanoparticles, ranging from endohedral fullerenes, carbon-based buckytubes to intermetallic or oxide nanoparticles. This combined approach is also the basis for the design of interfaces and heterostructures of superconducting materials, magnetic systems and molecular solids. In these heterostructures charge transfer effects at or across interfaces are decisive for the properties and functionality. An advantage of such interfaces is that they can be modified and engineered to a much greater extent than bulk Quantum Materials.

Building on the traditional strength in the field of Quantum Materials, and in order to strengthen in particular this research area and its potential for device applications, in 2013 the Center for Transport and Devices of Emergent Materials (CTD) has been founded together with the TU Dresden.

Our research teams search for new materials with the outlined unusual electronic properties and study their fundamental physical properties using a broad range of experimental techniques. Customized high resolution methodology is developed according to the specific scientific questions and phenomena, and finally, based on the experimental results, the chemistry, the morphology and the intrinsic physical properties of the materials are optimized with respect to technical applications. Some of the methodological developments of our institute push the limits of current condensed matter research. Such set-ups as well as the special infrastructure for materials synthesis are made available to cooperation partners at universities (crystal growth laboratory), worldwide users (ARPES measurement stations at the Berlin Synchrotron BESSY), or to industry partners (laboratory for spectroelectrochemistry).

Based on our scientific expertise, our methodological experience, and based on our dedicated knowledge of specific materials classes, we also perform application-driven research in close cooperation with various industry partners. In many of these activities key challenges of the modern industrial and information society are addressed. For example, there are projects in cancer research based on our knowledge of molecular nanostructures.

Additionally, our specific methodology and expertise for spectroelectrochemistry, magnetic materials, and oxide nanomaterials is used in industry projects concerning energy and/or mobility. The activities on novel magnetic materials are also motivated by the urgent issues of resources and sustainability. Moreover, the industry-oriented research of our institute includes since many years the topic "Surface Acoustic Waves (SAW)" dealing with innovative micro-acoustic components and devices as well as the associated high-tech materials and technologies. The IFW-driven "SAWLab Saxony - Competence Center for Acoustoelectronic Phenomena, Technologies and Devices" aims to bundle our profound SAW knowledge with experience and demands of several small and medium-sized Saxon high-tech companies fostering the close cooperation of our institute with the regional industry.

Facilities at IFF

  • Electron Energy Loss Spectroscopy (EELS)
  • Photoemission Spectroscopy (PES), low energy photons (laser, gas discharge sources) and x-rays, angle-integrated and resolved operation
  • Photoemission Electron Microscopy (PEEM)
  • Transmission Electron Microscopy (TEM)
  • Optical Spectroscopy
  • 1-cubed-ARPES
  • NanoESCA -Lab-based ARPES
  • Bruker 4-circle x-ray diffractometer (KAPPA APEXII)
  • high-pressure x-ray diffraction setup
  • transmission EELS -TEM (JEM 2010f)
  • Floating zone furnaces with optical heating under pressure up to 150 bar
  • Bridgman-Stockbarger apparatus up to 1500°C
  • Bridgman-Stockbarger apparatus up to 1600°C
  • Hukin-type cold-crucible rf induction melting and casting device
  • Multianvil device for high pressure synthesis and crystal growth up to 6GPa pressure and up to 1500°C
  • Arc-melting devices with high vacuum conditions (~10-6mbar) and Ar gas inlet
  • Different tube and chamber furnaces up to 1800°C for synthesis and crystal growth
  • Thermoanalysis under well-defined atmospheres up to 2400°C
  • High-temperature optical microscope (temperature up to 1450°C)
  • Handling of quartz glass
  • Complete metallography and ceramography
  • Analytical scanning electron microscope EVOMA15 (Zeiss), with EDX & WDX
  • X-ray diffractometers: Guinier camera with image plate, Temperatures 10 K to 300 K (Huber), Laue diffraction camera, Single crystal diffractometer (Bruker KAPPA-APEX II, 30 K-1000 K)
  • Setup to measure nuclear magnetic resonance (NMR) in ferromagnets (TECMAG spectrometer, 0T, 1.5- 300 K, 10-500 MHz)

Electrical Transport

  • 3He/4He dilution refrigerators, pumped 3He, and variable-temperature inserts
    combined with high-field magnets (16 Tesla) or vector magnets (3D: 6T-2T-2T; 2D: 12T-1T)  

Thermal Transport

  • Pumped 3He and variable-temperature inserts
    300 mK to 350 K, 17 Tesla
  • Laser Flash Apparatus LFA 457MicroFlash
    Thermal Diffusivity measurements covering 150 K to 1000 K

Scanning Probe Microscopy

  • Variable Temperature Scanning Tunneling Microscope (STM)
    Base temperature: 30 K, UHV
  • High-Resolution STM
    Base temperature: 300mK, UHV, 9 Tesla, equipped for spin-polarized STM
  • Dip-stick STM
    Base temperature: 4.2K, 16 Tesla, in-situ cleaving mechanism
  • Room temperature Omicron UHV SEM with integrated STM
  • Magnetic force microscope (MFM)
    Nanoscan hr-MFM (room temperature, high vacuum)

Electron spin resonance

  • Two tunable high-frequency high-magnetic field ESR spectrometers based on the Millimeterwave Vector Network Analyzers and millimeterwave backward oscillators
    • frequency range 10 GHz - 1 THz
    • magnetic fields up to 16 Tesla (up to 11 Tesla with an optical magneto-cryostat)
    • Temperature range 0.3 – 300 K
  • Bruker 10 GHz (X-band) ESR Spectrometer(3.5 K - 300K, filed up to 1 T)

Thermodynamics

  • Quantum Design SQUID Magnetometer (5 T, 1.5-400 K, Oven (up to 800 K), Rotator, Ultra-Low-field option, Hydrostatic Pressure Cell up to 5 GPa)
  • Vibrating Sample Magnetometer (17 T, 2.5-300 K)
  • Alternating Gradient Magnetometer  MicroMag™ Model 2900 (Princeton Measurement Corp., 4-300 K, 1.2 T, 1 nemu rms)
  • Quantum Design PPMS (9 T, 0.5-350 K; Specific heat, AC-susceptibility, Torque-Magnetometer, Electrical+heat transport, Dilatometer)
  • Quantum Design SQUID-VSM (7 T, 1.8-400 K)
  • Magnetostriction (18 T, 2-300K), Thermal Expansion (18 T, 2-300 K)
  • Hydrostatic Pressure Cell (up to 5 GPa)AC-Susceptibility (AC-Dipstick; 0 T)

In addition to the in-house techniques, in cooperation with our partners we apply the following techniques:

  • Pulsed Field Magnetometer up to 60 T (with J. Wosnitza, FZD Rossendorf)

Nuclear magnetic resonance

Spectrometers

  • 3 Techmag 500 MHz Double Resonance Spektrometers
  • 1 Tecmag LapNMR 0.2 MHz - 125 MHz single Resonance NQR

Cryostats

  • 1 Oxford cryostat (1.5K - 500K)
  • 3 Janis cryostats (1.5K - 325K)

Fullerenes

  • Four fullerene generators of local design
  • Full set of chromatographic (HPLC) equipment for separation of fullerene mixtures, including recycling HPLC

Spectroelectrochemistry

The Center of Spectroelectrochemistry in IFW has state-of-the-art equipment and expertise for in situ studies of the electrochemical electron transfer using IR, Raman, ESR, NMR, UV-vis-NIR and luminescence techniques. This list of spectroelectrochemical techniques available in the Center is quite unique, also on an international level.

Electrochemistry + spectroscopic method(s):

  • In situ ESR spectroelectrochemistry
  • In situ UV-vis-NIR spectroelectrochemistry
  • In situ ESR/UV-vis-NIR spectroelectrochemistry
  • In situ NMR spectroelectrochemistry
  • In situ Luminescence spectroelectrochemistry
  • In situ IR spectroelectrochemistry
  • In situ Raman spectroelectrochemistry

The Surface Dynamics Group possesses or has easy access to all equipment needed for the work on modern SAW systems . This includes a variety of unique and state-of-the-art tools and instruments for advanced simulation and extensive evaluation of thin films and bulk samples, as well as for the precise characterization of microacoustic devices under different ambient conditions:

  • Proprietary software tools for
    - Searching for acoustic modes in material systems of crystal acoustics (incl. thin films and fluids) and calculation of all relevant parameters
    - Extraction of material properties from BAW and SAW measurements
    - Calculation of COM parameters for SAW device simulation (surface impedance method)
    - SAW device simulation on base of different methods and models (surface impedance method, BAW based models)
    - FEM simulation of SAW systems
  • Ultra high frequency vibrometer for SAW & BAW wavefield measurements (Polytec UHF-120)
  • Dedicated clustertool CARMEN for thin film deposition on piezo- and pyroelectric substrates for magnetron sputtering, e-beam evaporation and pre-treatment including in-situ measurement techniques
  • High-precision ultrasonic pulse-echo measurement system (RiTec 5000)
  • Customized laseracoustic devices (LAwave systems) for high-precision material characterization (bulk, thin films, temperature dependence)
  • Setup for high precision measurement of bulk sample mass densitity (single crystals etc.)
  • Brillouin light scattering measurement system (JRS)
  • Diverse setups for SAW-based microfluidics
  • In-situ measurement techniques for damage analysis on loaded SAW devices
  • Customized lifetime (TTF) measuring setups for SAW devices
  • Various ovens for thermal treatment and measurement up to 1200°C under different atmospheric conditions (vacuum, inert gas, forming gas)
  • Gas flow cryostats equipped for dielectric and ultrasonic measurements in the temperature range 4.2 K - 350 K
  • Diverse RF measurement devices up to 8.5 GHz (network analyzers, impedance/gain phase analyzers, digitizing oscilloscopes etc)
  • Equipment for measurement of electrical and mechanical thin film and bulk parameters (resistivity, polarization, pyroelectricity, hardness, thickness)

IFF Publications (2020-2019)

Journal Papers

2020 - M. Kiani, N. Du, M. Vogel, J. Raff, U. Hübner, I. Skorupa, D. Bürger, S. Schulz, O.G. Schmidt, D. Blaschke, H. Schmidt
Disturbing-Free Determination of Yeast Concentration in DI Water and in Glucose Using Impedance Biochips
Biosensors : open access journal | Volume: 10 | Issue: 1 | P. 7/1-17 | URL

2020 - K. Bokai, A. Tarasov, V. Shevelev, O. Vilkov, A. Makarova, D. Marchenko, A. Petukhov, M. Muntwiler, A. Fedorov, V. Voroshnin, L. Yashina, C. Laubschat, D. Vyalikh, D. Usachov
Hybrid h-BN–Graphene Monolayer with B–C Boundaries on a Lattice-Matched Surface
Chemistry of Materials | Volume: 32 | Issue: 3 | P. 1172-1181 | URL

2020 - R. Weser, A. Darinskii, M. Weihnacht, H. Schmidt
Experimental and numerical investigations of mechanical displacements in surface acoustic wave bounded beams
Ultrasonics | URL

2019 - M. Kiani, N. Du, M. Vogel, J. Raff, U. Hübner, I. Skorupa, D. Bürger, S. Schulz, O.G. Schmidt, H. Schmidt
P-N Junction-Based Si Biochips with Ring Electrodes for Novel Biosensing Applications
Biosensors : open access journal | Volume: 9 | Issue: 4 | P. 120 | URL

2019 - S. Borisenko, D. Evtushinsky, Q. Gibson, A. Yaresko, K. Koepernik, T. Kim, M. Ali, J. van den Brink, M. Hoesch, A. Fedorov, E. Haubold, Y. Kushnirenko, I. Soldatov, R. Schäfer, R. Cava
Time-reversal symmetry breaking type-II Weyl state in YbMnBi2
Nature Communications | Volume: 10 | P. 3424/1-10 | URL

2019 - A. Fedorov, A. Yaresko, E. Haubold, Y. Kushnirenko, T. Kim, B. Büchner, S. Aswartham, S. Wurmehl, S. Borisenko
Energy scale of nematic ordering in the parent iron-based superconductor BaFe2As2
Physical Review B | Volume: 100 | Issue: 2 | P. 024517/1-7 | URL

2019 - K. Lenz, R. Narkowicz, K. Wagner, C. Reiche, J. Körner, T. Schneider, A. Kákay, H. Schultheiss, U. Weissker, D. Wolf, D. Suter, B. Büchner, J. Fassbender, T. Mühl, J. Lindner
Magnetization Dynamics of an Individual Single‐Crystalline Fe‐Filled Carbon Nanotube
Small | Volume: 2019 | P. 1904315/1-9 | URL

2019 - N. Puwenberg, C.F. Reiche, R. Streubel, M. Khan, D. Mukherjee, I.V. Soldatov, M. Melzer, O.G. Schmidt, B. Büchner, T. Mühl
Magnetization reversal and local switching fields of ferromagnetic Co/Pd microtubes with radial magnetization
Physical Review B | Volume: 99 | Issue: 9 | P. 094438/1-8 | URL

2019 - Y. Suhak, W.L. Johnson, A. Sotnikov, H. Schmidt, H. Fritze
Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures
MRS Advances | Volume: 4 | Issue: 9 | P. 515-521 | URL

2019 - R. Patra, R. Mattheis, H. Stöcker, M. Monecke, G. Salvan, R. Schäfer, O.G. Schmidt, H. Schmidt
Magnetooptical response of permalloy multilayer structures on different substrate in the IR-VIS-UV spectral range
Journal of Physics D: Applied Physics | URL

2019 - A. Makarova, L. Fernandez, D. Usachov, A. Fedorov, K. Bokai, D. Smirnov, C. Laubschat, D. Vyalikh, F. Schiller, J. Ortega
Oxygen Intercalation and Oxidation of Atomically Thin h-BN Grown on a Curved Ni Crystal
The Journal of Physical Chemistry C | Volume: 123 | Issue: 1 | P. 593-602 | URL

2019 - N. Sato, K. Schultheiss, L. Körber, N. Puwenberg, T. Mühl, A. Awad, S. Arekapudi, O. Hellwig, J. Fassbender, H. Schultheiss
Domain Wall Based Spin-Hall Nano-Oscillators
Physical Review Letters | Volume: 123 | Issue: 5 | P. 057204/1-5 | URL

2019 - S. Vegesna, D. Bürger, R. Patra, J. Dellith, B. Abendroth, I. Skorupa, O. Schmidt, H. Schmidt
Tunable large field magnetoconductance of ZnO, ZnMnO, and ZnCoO thin films
Journal of Applied Physics | Volume: 125 | Issue: 21 | P. 215305/1-14 | URL

2019 - E. Haubold, A. Fedorov, F. Pielnhofer, I. Rusinov, T. Menshchikova, V. Duppel, D. Friedrich, R. Weihrich, A. Pfitzner, A. Zeugner, A. Isaeva, T. Setti, Y. Kushnirenko, E. Rienks, T. Kim, E. Chulkov, B. Büchner, S. Borisenko
Possible experimental realization of a basic Z2 topological semimetal in GaGeTe
APL Materials | Volume: 7 | Issue: 12 | P. 121106/1-7 | URL

2019 - O. Vilkov, E. Krasovskii, A. Fedorov, A. Rybkin, A. Shikin, C. Laubschat, J. Budagosky, D. Vyalikh, D. Usachov
Angle-resolved secondary photoelectron emission from graphene interfaces
Physical Review B | Volume: 99 | Issue: 19 | P. 195421/1-10 | URL