Breakdown of three-dimensional Dirac semimetal state in pressurizedCd3As2

We report an observation of a pressure-induced breakdown of the three-dimensional Dirac semimetal (3DDSM) state in Cd3As2, evidenced by a series of in situ high-pressure synchrotron x-ray diffraction and single-crystal transport measurements. We find that Cd3As2 undergoes a structural phase transition from a metallic tetragonal phase in space group I4(1)/acd to a semiconducting monoclinic phase in space group P2(1)/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 3DDSM state in pressurized Cd3As2.