# Tunable magneto-optical properties of single-layer tin diselenide: From GW approximation to large-scale tight-binding calculations

## TL;DR

This paper develops a parameterized tight-binding model based on GW calculations to study the electronic and optical properties of single-layer tin diselenide under magnetic fields, enabling large-scale simulations.

## Contribution

A new tight-binding model derived from GW calculations for single-layer SnSe₂ is introduced, accurately capturing its electronic and optical properties under magnetic fields.

## Key findings

- Landau levels exhibit linear dependence on magnetic field and level index.
- Optical gap closely matches GW calculations and is tunable by magnetic field.
- Model enables large-scale exploration of SnSe₂ properties.

## Abstract

A parameterized tight-binding (TB) model based on the first-principles GW calculations is developed for single layer tin diselenide (SnSe$_2$) and used to study its electronic and optical properties under external magnetic field. The truncated model is derived from six maximally localized wannier orbitals on Se site, which accurately describes the quasi-particle electronic states of single layer SnSe$_2$ in a wide energy range. The quasi-particle electronic states are dominated by the hoppings between nearest wannier orbitals ($t_1$-$t_6$). Our numerical calculation shows that, due to the electron-hole asymmetry, two sets of Landau Level spectrum are obtained when a perpendicular magnetic field is applied. The Landau Level spectrum follows linear dependence on the level index and magnetic field, exhibiting properties of two-dimensional electron gas in traditional semiconductors. The optical conductivity calculation shows that the optical gap is very close to the GW value, and can be tuned by external magnetic field. Our proposed TB model can be used for further exploring the electronic, optical, and transport properties of SnSe$_2$, especially in the presence of external magnetic fields.