Rashba spin-orbit coupling significantly modifies the electronic band
structure in two-dimensional (2D) van der Waals (vdW) heterobilayers, which may
enhance their thermoelectric (TE) properties. In this study, we use
first-principles calculations and Boltzmann transport theory to explore the
strain effect on the TE performance of the 2D vdW heterobilayer
MoTe$_{2}$/PtS$_{2}$. A strong Rashba spin-splitting is observed in the valence
band, resulting in an increase in the Seebeck coefficient for p-type. The
lattice thermal conductivity of MoTe$_{2}$/PtS$_{2}$ is remarkably low about of
0.6 Wm$^{-1}$K$^{-1}$ at $T = 300$ K due to large anharmonic scattering.
Furthermore, biaxial strain enhances the power factor (PF) by introducing band
convergence. At a strain of 2\%, the optimal PF for the n-type material reaches
170 $\mu$W/cmK$^{2}$, indicating approximately 84.78\% increase compared to the
unstrained state (92 $\mu$W/cmK$^{2}$). Given the low lattice thermal
conductivity, the optimized figure of merit $ZT$ achieves up to 0.88 at 900 K
for n-type. Our findings indicate that MoTe$_{2}$/PtS$_{2}$ is a highly
promising candidate for 2D heterobilayer TE materials, owing to its strong
Rashba splitting and significant anharmonicity.

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