The quasi-two-dimensional electronic gas at the (111) SrTiO3-based heterostructure interfaces is described by a multi-band tight-binding model providing electronic bands in agreement at low energies with photoemission experiments. We analyze both the roles of the spin-orbit coupling and of the trigonal crystal field effects. We point out the presence of a regime with sizable strain where the band structure exhibits a Dirac cone whose features are consistent with \textit{ab-initio} approaches. The combined effect of spin-orbit coupling and trigonal strain gives rise to non-trivial spin and orbital angular momenta patterns in the Brillouin zone and to quantum spin Hall effect by opening a gap at the Dirac cone. The system can switch from a conducting to a topological insulating state \textit{via} modification of trigonal strain within a parameter range which is estimated to be experimentally achievable.
@article{arxiv.2109.11563,
title = {Strain-induced topological phase transition at (111) SrTiO$_3$-based heterostructures},
author = {Mattia Trama and Carmine Antonio Perroni and Vittorio Cataudella},
journal= {arXiv preprint arXiv:2109.11563},
year = {2022}
}