Dresden 2017 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Thermoelectric Materials

DS 17.2: Vortrag

Montag, 20. März 2017, 18:00–18:15, CHE 89

Electronic and thermoelectric properties of polar LaNiO3/SrTiO3(001) superlattices — •Benjamin Geisler1, Ariadna Blanca-Romero2, and Rossitza Pentcheva11Fakultät für Physik, Universität Duisburg-Essen, 47057 Duisburg, Germany — 2Department of Chemistry, Imperial College London, London, SW7 2AZ, United Kingdom

Advances in layer-by-layer fabrication techniques have made it possible to grow epitaxial transition metal oxide superlattices with atomic precision. We combine DFT+U calculations and Boltzmann transport theory to analyze the implications of the interface-dependent polar discontinuity in LaNiO3/SrTiO3(001) superlattices on the structural, electronic, and thermoelectric properties. While (LaO)+/(TiO2)0 interfaces result in an n-type superlattice, (NiO2)/(SrO)0 interfaces lead to p-type doping. We find that significant octahedral tilts are induced in the SrTiO3 region and that the La-Sr distances act as a fingerprint of the interface type. In contrast to the paradigmatic LaAlO3/SrTiO3 system, the electrostatic doping is mainly accommodated in the metallic NiO2 layers. We explain the electronic structure within the SrTiO3 band gap in terms of an orbital-selective quantization of Ni-3d-derived quantum well states. Complex cylindrical Fermi surfaces emerge which show a tendency towards nesting that depends on the interface polarity. Finally, we demonstrate that the thermoelectric response of our oxide superlattices can be selectively controlled by a targeted interface design.

Funding by the DFG within TRR 80 (G3 and G8) is acknowledged.

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