First-Principles Study of the Excitonic and Polaronic Effect of Hydride-Based Anti-perovskite Cu3HX (X = S, Se, Te)

초록

Copper-based anti-perovskites Cu3HX (X = S, Se, Te) are investigated using density functional theory (DFT) within the full-potential linearized augmented plane wave (FP-LAPW) method. Structural properties are computed using the PBE-GGA exchange potential, while the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential is employed for accurate band structure and density of states calculations. These materials crystallize in a cubic phase (Pm-3m) and exhibit indirect bandgaps of 1.36 eV (Cu3HS), 1.71 eV (Cu3HSe), and 1.75 eV (Cu3HTe) along X -> R. Small charge carrier effective masses enhance optical conductivity, with Cu3HS having the lowest exciton binding energy (0.037 eV). Mechanical analysis reveals that Cu3HSe has the highest Young's, shear, and bulk moduli, while Cu3HX (X = Se, Te) exhibit ductile behavior. Optical properties, including dielectric constants, polarization, and absorption spectra, are analyzed in detail. These findings provide fundamental insights into the physical properties of Cu3HX anti-perovskites.

키워드