How Can We Engineer Electronic Transitions Through Twisting and Stacking in TMDC Bilayers and Heterostructures? A First-Principles Approach

Yu-Hsiu Lin; William P. Comaskey; Jose L. Mendoza-Cortes

doi:10.1039/d5na00112a

paper

How Can We Engineer Electronic Transitions Through Twisting and Stacking in TMDC Bilayers and Heterostructures? A First-Principles Approach

arXiv:2405.06096 · doi:10.1039/d5na00112a

Abstract

Layered two-dimensional (2D) materials exhibit unique properties, expanding opportunities in material design. We investigate MX $_{2}$ transition metal dichalcogenides (TMDCs) (M = Mo, W; X = S, Se, Te) in homo- and heterobilayers with different stacking and twist angles. Twisted bilayers introduce MoirÃ© patterns, significantly altering electronic properties. Using first-principles Density Functional Theory (DFT) with range-separated hybrid functionals, we examine 30 MX $_{2}$ combinations, revealing how stacking and composition influence stability and band gap energy (E $_{g}$ ). Notably, the MoTe $_{2}$ /WSe $_{2}$ heterostructure with a 60\textdegree~shift maintains a direct band gap, highlighting its potential for applications. Homobilayers under low-strain conditions exhibit diverse stacking-dependent electronic behaviors, where MoS $_{2}$ , WS $_{2}$ , and WSe $_{2}$ transition between direct and indirect band gaps at specific twist angles. MoS $_{2}$ can even switch between semiconductor and metallic states. Critical twist angles (17.9\textdegree, 42.1\textdegree, 77.9\textdegree, and 102.1\textdegree) in twisted WS $_{2}$ and WSe $_{2}$ bilayers yield symmetric MoirÃ© patterns with tunable band gaps. Our findings emphasize that controlling heterostructures and twist angles is a powerful strategy for engineering electronic properties, offering a pathway for next-generation materials.

10 pages, 6 figures