  Two-dimensional transition metal dichalcogenides show great potential as
promising thermoelectric materials due to their lower dimensionality, the
unique density of states and quantum confinement of carriers. The effect of
mechanical strain on the thermoelectric performances of monolayer WS 2 has been
investigated using density functional theory associated with semiclassical
Boltzmann transport theory. The variation of Seebeck coefficient and band gap
with applied strain has followed the same type of trend. For n-type material
the relaxation time scaled power factor(S 2 {\sigma}/{\tau}) increases by the
application of compressive strain whereas for p- type material it increases
with the application of tensile strain. A 77% increase in the power factor has
been observed for the n-type material by the application of uniaxial
compressive strain. A decrease in lattice thermal conductivity with the
increase in temperature causes an almost 40% increase in ZT product under
applied uniaxial compressive strain. From the study, it is observed that
uniaxial compressive strain is more effective among all types of strain to
enhance the thermoelectric performance of monolayer WS 2 . Such strain induced
enhancement of thermoelectric properties in monolayer WS 2 could open a new
window for the fabrication of high-quality thermoelectric devices.
