Electronic and optical properties of monolayer tin diselenide: The effect of doping, magnetic field, and defects
Hongxia Zhong, Jin Yu, Xueheng Kuang, Kaixiang Huang, Shengjun Yuan
Abstract
A parametrized tight-binding (TB) model based on the first-principles calculations is developed for monolayer tin diselenide (${\mathrm{SnSe}}_{2}$). The truncated model is derived from six maximally localized Wannier orbitals, which accurately describe the quasiparticle electronic states of ${\mathrm{SnSe}}_{2}$ over a wide energy range. Based on this TB model, we investigate the effects of doping, magnetic field, and point defects on the electronic and optical properties of ${\mathrm{SnSe}}_{2}$. Our numerical calculation shows that the ambipolar optical absorption can be effectively modulated by the type of injected carriers. The plasmonic spectrum of doped ${\mathrm{SnSe}}_{2}$ consists of standard intraband two-dimensional excitation and interband transition modes, which damp into electron-hole pairs with different speed. In the presence of perpendicular magnetic field, monolayer ${\mathrm{SnSe}}_{2}$ behaves like traditional two-dimensional electron gas with equally spaced Landau-level spectrums and magneto-optical conductivity. Moreover, the appearance of point defects in the sample would generate sharp midgap states, activating new transitions in the optical spectrum. Our proposed TB model can be used for further exploring the electronic and optical properties of large-scale ${\mathrm{SnSe}}_{2}$ with complex structures beyond the first-principles calculations.