Signatures of Electronic Nematicity in (111) LaAlO$_3$/SrTiO$_3$ Interfaces

TL;DR

This paper reports the discovery of an electronic nematic phase at the (111) LaAlO3/SrTiO3 interface, which breaks rotational symmetry and is tunable by electric field, indicating a new phase of matter in oxide interfaces.

Contribution

It demonstrates the existence of an electronic nematic phase in 2D carrier gas at the (111) LAO/STO interface, a novel finding in oxide heterostructures.

Findings

Electronic nematic phase exists at the (111) LAO/STO interface.

The nematic phase onsets at low temperatures.

The phase is tunable by an electric field.

Abstract

Symmetry breaking is a fundamental concept in condensed matter physics whose presence often heralds new phases of matter. For instance, the breaking of time reversal symmetry is traditionally linked to magnetic phases in a material, while the breaking of gauge symmetry can lead to superfluidity/superconductivity. Nematic phases are phases in which rotational symmetry is broken while maintaining translational symme- try, and are traditionally associated with liquid crystals. Electronic nematic states where the or- thogonal in-plane crystal directions have different electronic properties have garnered a great deal of attention after their discovery in Sr$_3$Ru$_2$O$_7$, multiple iron based superconductors, and in the superconducting state of CuBiSe. Here we demonstrate the existence of an electronic ne- matic phase in the two-dimensional carrier gas that forms at the (111) LaAlO$_3$ (LAO)/SrTiO$_3$ (STO) interface that onsets at low temperatures, and is tunable by an electric field.