Electronic structure and photoconductivity properties of GaP under high pressure.

As a typical representative of Ga-based III-V compound semiconductor material, the pressure-induced structural phase transition of gallium phosphide (GaP) has received more attention, while the present work explains the electronic structure and photoconductivity properties under high pressure, especially. The paper focuses on the high-pressure electronic structure and photoconductivity properties up to 50.0 GPa in GaP, along with the ZB (zinc-blende structure) to RS (rock salt structure) phase structural transition using enthalpy calculation. The discontinuous thermal expansion coefficient and unit cell volume collapse by 15.0–15.5% are observed at around 39.2 GPa due to reversible structural phase transition under compression and decompression conditions, which is also reflected in the measured discontinuous Hall coefficient and conductivity at approximately 39.0 GPa. The computed semiconductor-to-metal transition is determined to occur at 24.5 GPa by band-gap closure in good agreement with the experimentally determined transition pressure. The light illumination provides a potential way to reduce conductivity without effect on pressure of phase transition. [ABSTRACT FROM AUTHOR]