Metallization and magnetoresistivity reversal of FePS3 under extreme pressure

The electrical transport behaviors of FePS3 are explored using first-principles calculation and in situ high-pressure electrical experiment up to 40 GPa. The electronic phase transitions are observed at approximately 5.5 GPa, 12.5 GPa, and 20.7 GPa by discontinuous electrical parameters and energy band structure. The intra- and inter-layer sliding is reflected from cell volume collapse and the lattice constants mutation at about 5.5 GPa. The metallization transition is determined by the computed energy-band closure, in good agreement with variable resistivity under different temperatures above 13.3 GPa. The sudden decrease in resistivity is jointly caused by the increase in carrier concentration and sudden increase in mobility at around 20.7 GPa, while the abrupt decrease of Hall coefficient is attributed to the increase of carrier concentration. The magnetoresistivity reversal is found at about 13.3 GPa from positive to negative due to semiconductor-to-metal transition. A reliable method is proposed to excite electrons in the valence band across the forbidden band into the empty conduction band to produce electron-hole pairs by pressure-induced photoconductivity effect.