Electronic structure of epitaxial perovskite films in the two-dimensional limit: Role of the surface termination

An often-overlooked property of transition metal oxide thin films is their microscopic surface structure and its effect on the electronic properties in the ultrathin limit. Contrary to the expected conservation of the perovskite stacking order in the (001) direction, heteroepitaxially grown SrIrO₃ films on TiO₂-terminated SrTiO₃ are found to exhibit a terminating SrO surface layer. [...]

Appl. Phys. Lett. 116, 201601 (2020)

Atomic-Scale Interface Structure in Domain Matching Epitaxial BaBiO₃ Thin Films Grown on SrTiO₃ Substrates

The electronic structures of BaBiO₃ (BBO) thin films grown on SrTiO₃ substrates are found to be thickness dependent. The origin of this behavior remains under debate and has been suggested to be attributed to the structural and compositional modifications at the BBO/SrTiO₃ interface during the first stage of film growth. [...]

Phys. Status Solidi RRL 2020, 2000054

Comparing magnetic ground-state properties of the V- and Cr-doped topological insulator (Bi,Sb)₂Te₃

An insulating ferromagnetic ground state is a fundamental prerequisite for the quantum anomalous Hall (QAH) effect observed in magnetically doped topological insulators such as ${(\text{Bi},\mathrm{Sb})}_2{\mathrm{Te}}_3$. So far, the QAH effect could only be induced by V and Cr doping, with V resulting in ferromagnetism with a higher $T_C$ and a more robust QAH state. [...]

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Phys. Rev. B 101, 045127 (2020)

Nanophysics at surfaces

The research activities of our group are concerned with the physics of low-dimensional systems, where the electron states resulting from dimensional confinement lead to unusual conduction properties and to phase transitions as a function of temperature.

Oxide interfaces

Our group focusses on the electronic structure of correlated systems in transition metal oxides (TMOs). Special interest lies in the interplay of different degrees of freedom (charge, spin, orbital, lattice) in the light of metal-insulator and other phase transitions.

Neutron and resonant X-ray spectroscopy

In our group we investigate complex, functional materials such as transition metal oxides, which are used in the emerging field of correlated nanoelectronics. Unlike with conventional semiconductors, exotic superconducting, orbital and magnetic states can be realized at the interfaces in layered structures comprising such materials.