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arXiv · 1808.03063

Band inversion driven by electronic correlations at the (111) LaAlO$_3$/SrTiO$_3$ interface

A. M. R. V. L. Monteiro·M. Vivek·D. J. Groenendijk·P. Bruneel·I. Leermakers·U. Zeitler·M. Gabay·A. D. Caviglia
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Abstract

Quantum confinement at complex oxide interfaces establishes an intricate hierarchy of the strongly correlated $d$-orbitals which is widely recognized as a source of emergent physics. The most prominent example is the (001) LaAlO$_3$/SrTiO$_3$(LAO/STO) interface, which features a dome-shaped phase diagram of superconducting critical temperature and spin-orbit coupling (SOC) as a function of electrostatic doping, arising from a selective occupancy of $t_{2g}$ orbitals of different character. Here we study (111)-oriented LAO/STO interfaces - where the three $t_{2g}$ orbitals contribute equally to the sub-band states caused by confinement - and investigate the impact of this unique feature on electronic transport. We show that transport occurs through two sets of electron-like sub-bands, and the carrier density of one of the sets shows a non-monotonic dependence on the sample conductance. Using tight-binding modeling, we demonstrate that this behavior stems from a band inversion driven by on-site Coulomb interactions. The balanced contribution of all $t_{2g}$ orbitals to electronic transport is shown to result in strong SOC with reduced electrostatic modulation.

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A. M. R. V. L. Monteiro, M. Vivek, D. J. Groenendijk, P. Bruneel, I. Leermakers, U. Zeitler, M. Gabay, A. D. Caviglia. 2018-08-09. Band inversion driven by electronic correlations at the (111) LaAlO$_3$/SrTiO$_3$ interface. https://doi.org/10.1103/physrevb.99.201102

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