Evidences for phase transition and metallization in β-In2S3 at high pressure

Abstract

The high-pressure characteristics including structural phase transition, vibration and electronic transport of β-In2S3 up to 43.0 GPa are determined using a diamond anvil cell (DAC) combined with AC impedance spectroscopy, Raman spectroscopy, atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). A structural phase transition and a semiconductor-to-metal transition are observed at ∼7 GPa and ∼41.2 GPa, respectively. When the pressure is released from 43.0 GPa, a single amorphous state is observed from Raman spectroscopy. We determine that the phase transition of metallization is irreversible after decompression from the pressure above 40 GPa. However, when the sample is decompressed from the pressure below 10 GPa, the phase transition is reversible. The unique properties displayed by β-In2S3 under different experimental pressure ranges can be reasonably explained by its crystalline structure observable from the microscopic observations of HRTEM and AFM images.