Hidden antiferromagnetism on the light-irradiated surface of bulk SrTiO3 and at the LaAlO3_SrTiO3 interfaces

TL;DR

This paper investigates the electronic properties and potential hidden antiferromagnetic order on the light-irradiated surfaces of SrTiO3 and at LaAlO3/SrTiO3 interfaces, revealing possible novel magnetic phases induced by illumination.

Contribution

It provides a symmetry-based analysis linking surface and interface states to potential antiferromagnetic phases in SrTiO3-based systems.

Findings

Identification of chiral band branches with lifted degeneracy

Proposal of a hidden antiferromagnetic phase in the surface states

Discussion of similar states at LaAlO3/SrTiO3 interfaces

Abstract

We study properties of electrons on illuminated surfaces of SrTiO3 with titanium dxz_dyz and dxy bands for their spectrum. Recently A. F. Santander-Syro et al [Nature Materials, 13, 1085 (2014)] found that the dxy bands actually comprise two chiral branches with the Kramers degeneracy at the zone center lifted in absence of a magnetic moment. From symmetry analysis of instabilities possible in the Fermi liquid with exchange interactions we identified the metallic in-layer state with the concrete antiferromagnetic phase and discuss if the same state materializes at conducting LaAlO3_SrTiO3 interfaces.