Pressure-induced superconductivity in GeAs

Abstract

We performed high-pressure Raman and resistance measurements on a two-dimensional monoclinic semiconductor GeAs. We discovered a superconductivity that emerges after the insulator-metal transition above 10 GPa, which is related to the structural transition. Our results indicate that the semiconducting monoclinic phase and rocksalt structure phase coexist above 10 GPa and structural transformation to the rocksalt phase is completed above 17∼18GPa. The maximum superconducting transition temperature Tc is about 8 K close to the structural transition boundary, and the Tc is gradually decreasing at higher pressures. Upon pressure release, the nonpolar rocksalt structure transforms to a polar tetragonal superconducting phase. Our first-principles calculations indicate that the relatively high Tc in the rocksalt phase is mainly due to the enhancement of the electron-phonon coupling. These results show that superconductivity in this material strongly depends on its structure, achieving maximum Tc in a higher-symmetry phase.

Source-reported materials — not catalogue approval

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