Quasiparticle Band Structure and Optical Properties of the Janus Monolayer and Bilayer SnSSe
Pan Wang, Yixin Zong, Hao Liu, Hongyu Wen, Hui‐Xiong Deng, Zhongming Wei, Haibin Wu, Jian‐Bai Xia
Abstract
Two-dimensional (2D) Janus materials with large exciton binding energies have attracted enormous attention for their novel photoelectric properties. Here, the quasiparticle (QP) band structures and optical properties of the Janus SnSSe monolayer and the SeSnS–SeSnS, SeSnS–SSnSe, and SSnSe–SeSnS bilayers are investigated using the more accurate GW approximation combined with the Bethe–Salpeter equation (BSE). First, the ab initio molecular dynamics (AIMD) and phonon spectrum calculations are performed, verifying the dynamic stability of monolayer SnSSe. In addition, the exciton binding energies of SnSSe monolayer and the SeSnS–SeSnS, SeSnS–SSnSe, and SSnSe–SeSnS bilayer are predicted to be 0.76, 0.21, 0.35, and 0.48 eV, respectively. Due to large excitonic effects, Janus SnSSe have great potential for nanoscale optoelectronic applications. These findings enrich the understanding of the physical properties of Janus SnSSe.