Electron Correlation Induced Spontaneous Symmetry Breaking and Weyl Semimetal Phase in a Strongly Spin-Orbit Coupled System

TL;DR

This paper theoretically investigates how strong electron correlations and spin-orbit coupling induce spontaneous symmetry breaking and lead to a Weyl semimetal phase in a three-dimensional Dirac system, revealing new topological phases.

Contribution

It demonstrates that electron correlations can spontaneously break symmetries and induce Weyl semimetal phases in strongly spin-orbit coupled systems, extending understanding of topological phase transitions.

Findings

Symmetry breaking occurs under strong correlations and spin-orbit coupling.

Electron correlation enhances Weyl semimetal phase in presence of magnetic impurities.

Phase diagram includes topological insulator, Weyl semimetal, and normal insulator phases.

Abstract

We study theoretically the electron correlation effect in a three-dimensional Dirac fermion system which describes a topologically nontrivial state. It is shown within the mean-field approximation that time-reversal and inversion symmetries of the system are spontaneously broken in the region where both spin-orbit coupling and electron correlation are strong. This phase is considered as an analog of that in the lattice quantum chromodynamics. It is also shown that in the presence of magnetic impurities, electron correlation enhances the appearance of the Weyl semimetal phase between the topological insulator phase and the normal insulator phase.