Giant conductivity enhancement: Pressure-induced semiconductor-metal phase transition in Cd_(0.90)Zn_(0.1)Te

摘要

Element doping and pressure compression may change material properties for improved performance in applications. We report pressure-induced metallization in the semiconductor Cd0.90Zn0.1Te. Transport measurements showed an overall resistivity drop of 11 orders of magnitude under compression up to 12 GPa, which is indicative of a metallization transition. X-ray diffraction measurements revealed that the sample underwent a structural transition from a cubic-F4 (3) over barm phase (zinc blende) to a cubic-Fm (3) over barm phase (rock salt) at about 5.5 GPa, followed by another transition to an orthorhombic Cmcm structure at 13 GPa. A huge volume collapse of about 18% was observed during the first phase transition, suggesting a first-order phase transition. The disappearance or weakening of Raman modes, temperature-dependent resistivity, and ab initio calculation results depict the metallic nature of both the rock-salt and Cmcm phases. The band structure changes and increased carrier density (especially at the first structural transition) are likely a consequence of the structural transition.