Emergence of Two High-pressure Superconducting Phases in Pressurized Optical Semiconductor GaP

Abstract

Abstract Pressure engineering in semiconductors leads to a variety of novel physical phenomena and has recently obtained considerable attention. Here we report on pressure-induced superconductivity in III-V gallium phosphide (GaP), a commercially important semiconductor that exhibits excellent optical performances. We show that the emergence of superconductivity is accompanied by concurrence of piezochromic transition and metallization, and can be correlated to a structural transition from cubic to orthorhombic phase. In line with structural origin of the superconductivity, the critical temperature Tc decreases monotonically with increasing pressure up to ~ 50 GPa. Moreover, the superconductivity could be preserved toward ambient pressure because of the irreversibility of the structural transition. Nevertheless, the superconducting transition displays evident broadening associated with the presence of amorphization in the depressurized sample. The synchronous evolution of the structural and electronic properties not only documents a vivid structure–property relationship, but also sheds light on exploring novel functionalities by means of pressure treatment.