Giant conductivity enhancement: Pressure-induced semiconductor-metal phase transition in Cd0.90Zn0.1Te

Abstract

Element doping and pressure compression may change material properties for improved performance in applications. We report pressure-induced metallization in the semiconductor $\mathrm{C}{\mathrm{d}}_{0.90}\mathrm{Z}{\mathrm{n}}_{0.1}\mathrm{Te}$. 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-$F4\overline{3}m$ phase (zinc blende) to a cubic-$Fm\overline{3}m$ 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 $ab\phantom{\rule{0.16em}{0ex}}initio$ 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.