Time-reversal symmetry breaking in a square lattice

TL;DR

This paper investigates how quantum interference effects that break time-reversal symmetry influence the bulk conductivity in a 2D square lattice, revealing quantized conductivity behavior dependent on electric field strength.

Contribution

It provides a detailed numerical analysis of nonlinear response and demonstrates conditions for non-zero conductivity at zero electric field in a strongly spin-orbit coupled lattice.

Findings

Quantized conductivity depends on electric field intensity.

Non-zero conductivity persists at zero electric field under certain conditions.

Quantum interference effects break time-reversal symmetry in the system.

Abstract

The bulk conductivity of a two-dimensional system is studied assuming that quantum interference effects break time-reversal symmetry in the presence of strong spin-orbit interaction and strong lattice potential. The study is carried out by direct diagonalization in order to explore the nonlinear-response regime. The system displays a quantized conductivity that depends on the intensity of the electric field and under specific conditions the conductivity limit at zero electric field shows a nonvanishing value.