Landau level splitting in Cd3As2 under high magnetic fields

TL;DR

This study reports the first observation of Landau level splitting in the topological Dirac semimetal Cd3As2 under high magnetic fields, revealing symmetry breaking effects and potential pathways to Weyl semimetal phases.

Contribution

It provides experimental evidence of Landau level splitting in Cd3As2, demonstrating how high magnetic fields can break symmetries and induce phase transitions in topological Dirac semimetals.

Findings

Landau level splitting observed under high magnetic fields

Berry phase shows angular dependence and crossover behavior

Symmetry breaking can lead to Weyl semimetal phase

Abstract

Three-dimensional topological Dirac semimetals (TDSs) are a new kind of Dirac materials that exhibit linear energy dispersion in the bulk and can be viewed as three-dimensional graphene. It has been proposed that TDSs can be driven to other exotic phases like Weyl semimetals, topological insulators and topological superconductors by breaking certain symmetries. Here we report the first transport experiment on Landau level splitting in TDS Cd3As2 single crystals under high magnetic fields, suggesting the removal of spin degeneracy by breaking time reversal symmetry. The detected Berry phase develops an evident angular dependence and possesses a crossover from nontrivial to trivial state under high magnetic fields, a strong hint for a fierce competition between the orbit-coupled field strength and the field-generated mass term. Our results unveil the important role of symmetry breaking in TDSs and further demonstrate a feasible path to generate a Weyl semimetal phase by breaking time reversal symmetry.