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Research Activities:
1. Superconductivity:
- FeAs-based superconductors
- mechanism of
superconductivity in the cuprate superconductors: symmetry of the order
parameter, phase diagram, competion/coexistence of ordering phenomena
- experimental methods:
tunneling spectroscopy, measurement of the electrical and thermal
transport properties, quantum oscillations
- superconducting devices: Josephson junctions,
superconducting Quantum Interference Devices, superconducting
transistors
2. Solid State Quantum Systems and Quantum Information Processing:
- fabrication and characterization of superconducting quantum circuits: preparation,
manipulation, coupling, and read out of superconducting qubits
- realization of superconducting qubits using π-Josephson junctions
- study of decoherence in solid state qubits
- superconducting circuit quantum electrodynamics (c-QED)
- nano-electromechanical systems
3. Magnetism and Spintronics:
- multiferroic materials, strain control of magnetism
- spin caloritronics, spin pumping
- ferromagnetic semiconductors
- fabrication of magnetic tunnel junctions for magnetoresistive sensors or magnetic
memories (Magnetic Random Access Memory: MRAM); use of oxide materials
with large spin polarization (double perovskites, magnetite, doped
manganites)
- electrical transport and noise properties of spintronic devices and magnetoresistive
materials
- surface and interface properties of magnetic heterostructures
4. Mesoscopic Systems and Nanotechnology:
- fabrication of
metallic nanostructures (normal conducting, superconducting or
ferromagnetic
using electron beam lithography
- electrical
transport
and noise properties of mesoscopic metallic systems (universal conductance
fluctuations, correlation effects, shot and 1/f noise, nonequilibrium
effects)
- mesoscopic superconductor/normal metal, ferromagnet/normal metal or
ferromagnet/superconductor structures
- devices based on quantum effects
5. Physics of Complex Transition Metal Oxides:
- interplay
between
spin, charge, structural and orbital degrees of freedom: orbital and
charge ordering, metal/insulator transition magnetism, transport
properties
experimental
techniques:
specific heat, thermal expansion and magnetization as a function of
temperature (mK to 300K) and applied magnetic field (up to 17 Tesla)
- colossal
magnetoresistance in doped manganites
- spin dependent
transport
6. Materials Science:
- epitaxial
growth of
oxide materials (e.g. cuprate superconductors, doped manganites, double
perovskites, magnetite, ZnO, titanates, nickelates) as the basis of oxide
electronics
experimental
methods:
UHV-Laser-Molecular Beam Epitaxy with in-situ analysis (e.g.. AFM/STM,
RHEED)
- development
of growth techniques for single crystals and ceramics of oxide materials
- development of
patterning technique for oxide materials
Many of our research activities are carried out in close collaboration with other
universities and research all over the world. With respect to
application oriented research there is also a close collaboration with
industry.
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