Temperature induced lattice vibration and electronic structural behaviors of CrPS4

Abstract

The temperature-dependent lattice vibration and electronic structure behaviors are undoubtedly worthy of theoretical and experimental attention for two-dimensional (2D) van der Waals (vdW) semiconductor CrPS₄. Enhanced thermal vibration leads to lattice distortion of tightly packed S atoms and monoclinically metrically arranged Cr and P atoms. The A_I-VI-type Raman modes (298–673 K) exhibit continuous intensity weakening with a blue shift, whereas the B_I-II-type Raman modes first reach minimum intensity at 373 K before transforming into the B_III mode, with an initial intensity enhancement followed by weakening accompanied by a red shift. The lattice symmetry destruction theoretically promotes the temperature-induced metallization transition at about 977 K, characterized by enhanced contributions from s-orbitals (P and S atoms) near the Fermi level (E_F), with a distinct trend of electronic state delocalization under action of temperature. This work thus elucidates fundamental insights into their potential as temperature-adaptive electronic devices in the CrPS₄-type family.