# Instability of Dirac semimetal phase under strong magnetic field

## TL;DR

This paper investigates the instability of Dirac semimetals under strong magnetic fields, predicting new phases such as charge density waves and polarized nematic states, with experimental signatures suggested for their identification.

## Contribution

It provides a systematic mean-field analysis of Dirac semimetal instability under magnetic fields, predicting novel phases and experimental detection methods.

## Key findings

- Charge density wave phase predicted for untilted bands
- Polarized nematic phase predicted for tilted bands
- Experimental signatures include anisotropic transport and Raman scattering

## Abstract

The quantum limit can be easily reached in the Dirac semimetals under the magnetic field, which will lead to some exotic many-body physics due to the high degeneracy of the topological zeroth Landau bands (LBs). By solving the effective Hamiltonian, which is derived by tracing out the high energy degrees of freedom, at the self-consistent mean field level, we have systematically studied the instability of Dirac semimetal under a strong magnetic field. A charge density wave (CDW) phase and a polarized nematic phase formed by "exciton condensation" are predicted as the ground state for the tilted and untilted bands, respectively. Furthermore, we propose that, distinguished from the CDW phase, the polarized nematic phase can be identified in experiments by anisotropic transport and Raman scattering.