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Computational 2D Materials Database : Electronic Structure of Transition-Metal Dichalcogenides and Oxides

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Abstract

We present a comprehensive first-principles study of the electronic structure of 51 semiconducting monolayer transition-metal dichalcogenides and -oxides in the 2H and 1T hexagonal phases. The quasiparticle (QP) band structures with spin-orbit coupling are calculated in the G(0)W(0) approximation, and comparison is made with different density functional theory descriptions. Pitfalls related to the convergence of GW calculations for two-dimensional (2D) materials are discussed together with possible solutions. The monolayer band edge positions relative to vacuum are used to estimate the band alignment at various heterostructure interfaces. The sensitivity of the band structures to the in-plane lattice constant is analyzed and rationalized in terms of the electronic structure. Finally, the q-dependent dielectric functions and effective electron and hole masses are obtained from the QP band structure and used as input to a 2D hydrogenic model to estimate exciton binding energies. Throughout the paper we focus on trends and correlations in the electronic structure rather than detailed analysis of specific materials. All the computed data is available in an open database.

CHEMISTRY NANOSCIENCE MATERIALS SINGLE-LAYER MOS2 MONOLAYER MOS2 VALLEY POLARIZATION BILAYER MOS2 STATES HETEROSTRUCTURES SEMICONDUCTOR NANOSHEETS DISULFIDE DIODES Band structure Binding energy Calculations Computation theory Electronic structure Heterojunctions Monolayers Transition metal compounds Transition metals Dielectric functions Effective electrons Exciton-binding energy First-principles study Heterostructure interfaces Spin-orbit couplings Transition metal dichalcogenides Two Dimensional (2 D) Density functional theory cond-mat.mtrl-sci