Electronic structure, optical properties, and phonon transport in Janus monolayer PtSSe via first-principles study

ABSTRACT

Motivated by the synthesis of a Janus monolayer, the new PtSSe transition-metal dichalcogenide (TMD) have attracted remarkable attention due to their characteristic properties. In this work, we calculated the electronic structure, optical properties, and the thermal conductivity of the PtSSe monolayers, and performed a detailed comparison with other TMDs (monolayer PtS₂ and PtSe₂) using first-principles calculations. The calculated band gaps of the PtS₂, PtSSe, and PtSe₂ monolayers were 1.76, 1.38, and 1.21 eV, respectively, which are in good agreement with experimental data. At the same time, we observed a larger spin-orbit splitting in the electronic structure of PtSSe monolayers. The optical properties were also calculated and a significant red shift was observed from the PtS₂ to PtSSe to PtSe₂ monolayers. The lattice thermal conductivity of the PtSSe monolayer at room temperature (36.19 W/mK) is significantly lower than that of the PtS₂ monolayer (54.25 W/mK) and higher than that of the PtSe₂ monolayer (18.07 W/mK). Our results show that the PtSSe monolayer breaks structural symmetry and has the same ability to reduce the thermal conductivity as MoSSe and ZrSSe monolayers due to the shorter group velocity and the lower converged phonon scattering rate. These results may stimulate further studies on the electronic structure, optical properties, and thermal conductivity of the PtSSe monolayer in both experimental synthesis and theoretical efforts.

KEYWORDS:

• Janus PtSSe monolayer
• Lattice thermal conductivity
• Electronic structure
• Optical properties
• First-principles calculation

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [Grant Number grant No. 11504035]; Science Challenge Project: [Grant Number grant No. TZ2016001].