First principles study and empirical parametrization of twisted bilayer MoS2 based on band-unfolding

Yaohua Tan, Fan W. Chen, and Avik W. Ghosh, Applied Physics Letters , 109 (101601) (2016).
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Abstract

We explore the band structure and ballistic electron transport in twisted bilayer \( MoS_2 \) using the density functional theory. The sphagetti like bands are unfolded to generate band structures in the primitive unit cell of the original 2H \( MoS_2 \) bilayer and projected onto the original bands of an individual layer. The corresponding twist angle dependent bandedges are extracted from the unfolded band structures. Based on a comparison within the same primitive unit cell, an efficient two band effective mass model for indirect \( \Gamma_V \) and \( \Lambda_C \) valleys is created and parametrized by fitting to the unfolded band structures. With the two band effective mass model, we calculate transport properties—specifically, the ballistic transmission in arbitrarily twisted bilayer \( MoS_2 \).