\textit{Ab-initio} Tight-Binding Hamiltonian for Transition Metal Dichalcogenides

TL;DR

This paper develops an accurate, minimal-basis tight-binding Hamiltonian for transition metal dichalcogenides, derived from ab-initio DFT calculations and Wannier functions, enabling detailed studies of electronic properties and many-body effects.

Contribution

The paper introduces a new ab-initio tight-binding Hamiltonian for TMDCs based on maximally localized Wannier functions, including spin-orbit coupling and interlayer interactions, with simplified models for low-energy physics.

Findings

Provides a minimal basis tight-binding model for TMDCs

Includes spin-orbit coupling and interlayer interactions

Enables analysis of optical transitions and Berry curvature

Abstract

We present an accurate \textit{ab-initio} tight-binding hamiltonian for the transition-metal dichalcogenides, MoS$_2$, MoSe$_2$, WS$_2$, WSe$_2$, with a minimal basis (the \textit{d} orbitals for the metal atoms and \textit{p} orbitals for the chalcogen atoms) based on a transformation of the Kohn-Sham density function theory (DFT) hamiltonian to a basis of maximally localized Wannier functions (MLWF). The truncated tight-binding hamiltonian (TBH), with only on-site, first and partial second neighbor interactions, including spin-orbit coupling, provides a simple physical picture and the symmetry of the main band-structure features. Interlayer interactions between adjacent layers are modeled by transferable hopping terms between the chalcogen \textit{p} orbitals. The full-range tight-binding hamiltonian (FTBH) can be reduced to hybrid-orbital k $\cdot$ p effective hamiltonians near the band extrema that captures important low-energy excitations. These \textit{ab-initio} hamiltonians can serve as the starting point for applications to interacting many-body physics including optical transitions and Berry curvature of bands, of which we give some examples.