Theoretically proposed another stable polymorph of two-dimensional penta-PdPSe

TL;DR

This paper theoretically proposes a new stable polymorph of 2D penta-PdPSe, called the beta phase, demonstrating its stability, electronic properties, and potential for nanodevice applications.

Contribution

The study introduces the beta phase of penta-PdPSe as a new stable 2D material with detailed stability analysis and electronic property characterization.

Findings

Beta penta-PdPSe is thermodynamically, dynamically, mechanically, and thermally stable.

It is a wide band gap semiconductor with an indirect band gap of 1.58 eV.

The material is suitable for electronic and optical nanodevices.

Abstract

The theoretical discovery of new and stable 2D penta materials has stimulated the technological advancement due to the anticipated exotic properties of such structure, including the recent $\alpha$ phase and $\beta$ phase of penta-NiPS based on first-principles calculations. Inspired by the similarity between the theoretically proposed penta-NiPS and the experimentally synthesized ($\alpha$ phase) of penta-PdPSe, we preposed herein the $\beta$ phase penta-PdPSe as a new member of the penta-2D materials. Comprehensive analysis indicated that the $\beta$ phase penta-PdPSe is thermodynamically, dynamically, mechanically, and thermally stable, similar to the NiPS analog. It was found that $\beta$ penta-PdPSe is a wide band gap semiconductor with an indirect band gap of 1.58 eV, significantly lower than 2.15 eV for the $\alpha$ phase. Moreover, the two polymorphs of penta-PdPSe are a soft material with 2D Young's modulus of $E_a$ = 151 Nm$^-1$ and $E_b$ = 123 Nm$^-1$ for the $\beta$ phase, to be compared with $E_a$ = 155 Nm$^-1$ and $E_b$ = 113 Nm$^-1$ for the $\alpha$ phase. The calculated adsorption coefficient shows that $\beta$ phase penta-PdPSe is acceptable for electronic and optical nanodevice.