1 research outputs found
Ab-initio study of the energy competition between \Gamma and K valleys in bilayer transition metal dichalcogenides
Moir\'e engineering in two-dimensional van der Waals bilayer crystals has
emerged as a flexible platform for controlling strongly correlated electron
systems. The competition between valleys for the band extremum energy position
in the parent layers is crucial in deciding the qualitative nature of the
moir\'e Hamiltonian since it controls the physics of the moir\'e minibands.
Here we use density functional theory to examine the competition between K and
for the valence band maximum in homo- and hetero-bilayers formed from
the transition metal dichalcogenides (TMD), MX\{_2} where M=Mo,W and X=S,Se,Te.
We shed light on how the competition is influenced by interlayer separation,
which can be modified by applying pressure, by external gate-defined electric
fields, and by transition metal atom d-orbital correlations. Our findings are
related to several recent experiments, and contribute to the development of
design rules for moir\'{e} materials