First-principles LCAO study of the low and room temperature phases of CdPS$_3$

TL;DR

This study uses first-principles calculations to analyze the electronic and atomic structures of CdPS3 in its low and room temperature phases, revealing how pressure influences its band gap.

Contribution

It provides a detailed first-principles analysis of CdPS3's phases, including pressure effects on the band gap, with results aligning well with experimental data.

Findings

The calculated band gaps closely match experimental values.

Pressure causes the band gap to reach a maximum at different pressures for each phase.

The maximum band gap values are approximately 4 eV and 3.6 eV for the R3 and C2/m phases, respectively.

Abstract

The electronic and atomic structure of a bulk 2D layered van-der-Waals compound CdPS3 was studied in the low (R3) and room (C2/m) temperature phases using first-principles calculations within the periodic linear combination of atomic orbitals method with hybrid meta exchange-correlation M06 functional. The calculation results reproduce well the experimental crystallographic parameters. The value of the indirect band gap Eg=3.4 eV for the room-temperature monoclinic C2/m phase is close to the experimental one, while the indirect band gap Eg=3.3 eV was predicted for the low-temperature trigonal R3 phase. The effect of hydrostatic pressure on the band gap in both phases was studied in the pressure range from 0 to 40 GPa. In both cases, the pressure dependence of the band gap passes through a maximum, but at different pressures. In the R3 phase, the band gap reaches its maximum value of ~4 eV at ~30 GPa, whereas in the C2/m phase, the maximum value of ~3.6 eV is reached already at ~8 GPa.