Breakdown of Three-dimensional Dirac Semimetal State in pressurized Cd3As2

TL;DR

This study demonstrates that applying pressure to Cd3As2 causes a structural phase transition that destroys its 3D Dirac semimetal state, evidenced by changes in crystal structure and electronic properties.

Contribution

First experimental observation of pressure-induced breakdown of the 3D Dirac semimetal state in Cd3As2 through combined structural and transport measurements.

Findings

Structural phase transition at 2.57 GPa from tetragonal to monoclinic

Emergence of an electronic energy gap under pressure

Changes in Hall resistivity and electron mobility indicating breakdown

Abstract

We report the first observation of a pressure-induced breakdown of the 3D-DSM state in Cd3As2, evidenced by a series of in-situ high-pressure synchrotron X-ray diffraction (XRD) and single crystal transport measurements. We find that Cd3As2 undergoes a structural phase transition from a metallic tetragonal (T) phase in space group I41/acd to a semiconducting monoclinic (M) phase in space group P21/c at critical pressure 2.57 GPa, above this pressure, an activation energy gap appears, accompanied by distinct switches in Hall resistivity slope and electron mobility. These changes of crystal symmetry and corresponding transport properties manifest the breakdown of the 3D-DSM state in pressurized Cd3As2.