Strain Effect on Rashba Splitting and Phonon Scattering to Improve Thermoelectric Performance of 2D Heterobilayer MoTe₂/PtS₂

High Resolution Image Download MS PowerPoint Slide 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 effect of strain on the TE performance of 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 the p-type. The lattice thermal conductivity of MoTe 2 /PtS 2 is remarkably low, about 0.6 W m –1 K –1 at 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 μW/cmK 2, indicating an approximately 84.78% increase compared to the unstrained state (92 μW/cmK 2 ). Given the low lattice thermal conductivity, the optimized figure of merit ZT achieves up to 0.88 at 900 K for the 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.