Stacking effects on the electronic and optical properties of bilayer transition metal dichalcogenides MoS2, MoSe2, WS2, and WSe2

Author(s)

Jiangang He, Kerstin Hummer, Cesare Franchini

Abstract

Employing the random phase approximation we investigate the binding

energy and Van der Waals (vdW) interlayer spacing between the two layers

of bilayer transition metal dichalcogenides MoS2, MoSe2, WS2, and WSe2

for five different stacking patterns, and examine the stacking-induced

modifications on the electronic and optical/excitonic properties within

the GW approximation with a priori inclusion of spin-orbit

coupling and by solving the two-particle Bethe-Salpeter equation. Our

results show that for all cases, the most stable stacking order is the

high symmetry AA′ type, distinctive of the bulklike 2H symmetry, followed by the AB stacking fault, typical of the 3R

polytypism, which is by only 5 meV/formula unit less stable. The

conduction band minimum is always located in the midpoint between K and Γ, regardless of the stacking and chemical composition. All MX2

undergo an direct-to-indirect optical gap transition going from the

monolayer to the bilayer regime. The stacking and the characteristic vdW

interlayer distance mainly influence the valence band splitting at K

and its relative energy with respect to Γ, as well as, the electron-hole binding energy and the values of the optical excitations.

Organisation(s)

Computational Materials Physics

External organisation(s)

Cornell University

Journal

Physical Review B

Volume

No. of pages

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.89.075409

Publication date

02-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

103009 Solid state physics, 103015 Condensed matter, 103025 Quantum mechanics, 103036 Theoretical physics

Keywords

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