AVS 63rd International Symposium & Exhibition
    2D Materials Focus Topic Thursday Sessions
       Session 2D+MI-ThM

Paper 2D+MI-ThM11
Modeling Excitons in Transition-Metal Dichalcogenides

Thursday, November 10, 2016, 11:20 am, Room 103B

Session: Properties of 2D Materials including Electronic, Magnetic, Optical, Mechanical, Thermal Properties
Presenter: Daniel Gunlycke, Naval Research Laboratory
Authors: F. Tseng, NRC Research Associate
E. Simsek, George Washington University
D. Gunlycke, Naval Research Laboratory
Correspondent: Click to Email
Using a triangular lattice exciton (3ALE) model, we explore exciton states in semiconducting monolayer transition-metal dichalcogenides. We show that the hydrogen model for excitons breaks down due to lattice effects and that the excitons are neither Wannier nor Frenkel excitons and instead span an intermediate size regime. The model is formulated on sparse form in direct space, leading to a computationally efficient N log(N) scaling and the ability to calculate over lattice grids with tens of thousands of sites, more than sufficient to converge exciton states in this intermediate exciton regime. In this presentation, we will also discuss the Coulomb potential generated from a dielectric substrate and how the exciton binding energies could be tuned by the thickness and permittivity of an oxide layer.