Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 56: Poster Session: Low-Dimensional Systems
TT 56.10: Poster
Wednesday, March 22, 2017, 15:00–19:00, P2-OG4
Thickness dependent electronic and structural transition in BaBiO3 thin films on SrTiO3 — •Michael Zapf, Sebastian Elsässer, Martin Stübinger, Jean Geurts, Michael Sing, and Ralph Claessen — Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Germany
BaBiO3 (BBO), the parent material of the high-TC superconductor Ba1−xKxBiO3 (TC=30 K), has recently been proposed to be a large gap topological insulator, when heavily n-doped. This state may be accessed experimentally by electric gating and doping of BBO thin films as single or multilayer structures.
To investigate, as a first step, the properties of pristine BBO in the thin film limit, we have grown a series of BBO films of various thicknesses on SrTiO3 with pulsed laser deposition (PLD). We found significant modulations of the structural and electronic characteristics of the films. Raman spectroscopy indicates a reduction of the lattice symmetry from a cubic to a distorted perovskite lattice as in bulk-like BBO at a thickness of a few unit cells. Beyond this thickness, photoemission valence band spectra of the thin films resemble the spectral shape known from BBO single crystals. Further photoemission measurements show that this structural and electronic crossover is determined by significant stoichiometry deviations occurring at the beginning of BBO deposition.