Time-Reversal Symmetry Protected Transport at Correlated Oxide Interfaces

TL;DR

This paper demonstrates the existence of time-reversal symmetry protected transport at LaAlO3/SrTiO3 interfaces, revealing a new platform for quantum engineering with exotic topological states in correlated oxides.

Contribution

It provides experimental evidence of TRS-protected subbands in oxide interfaces, linking them to Rashba effects and ferroelastic domain walls, a novel insight in correlated oxide physics.

Findings

Observation of a TRS-protected subband causing quantum oscillations.

Identification of a Rashba model with strong spin-orbit coupling.

Transport occurs along quasi-1D ferroelastic domain walls with Dirac topology.

Abstract

Time-reversal symmetry (TRS) protection is core to topological physics, yet its role in correlated oxides-typically non-topological-remains underexplored. This limit hampers the potential in engineering exotic quantum states by fusing TRS protection and the rich emergent phenomena in the oxide platform. Here, we report evidence of a TRS-protected subband at oxygen vacancy-free LaAlO3/SrTiO3 interfaces. This subband causes a low-field quantum oscillation with anomalous characters: exceptionally light electron mass, aperiodicity, and susceptibility to magnetic fields. All findings align with a Rashba model in which TRS-protected transport occurs along quasi-1D ferroelastic domain walls, which possess a Dirac band topology and a giant Rashba spin-orbit coupling, two orders stronger than the 2D interface. Our results deepen the understanding of SrTiO3-based electron systems, unveiling an appealing new platform for quantum engineering.