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

2025/04/23 by Van Thanh, Vuong, Hung, Nguyen Tuan
#Applied Physics (physics.app-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)

paper · doi:10.48550/arxiv.2504.16781

Abstract

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 MoTe₂/PtS₂. 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 MoTe₂/PtS₂ is remarkably low about of 0.6 Wm^-1K^-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 μW/cmK², indicating approximately 84.78% increase compared to the unstrained state (92 μW/cmK²). 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 MoTe₂/PtS₂ is a highly promising candidate for 2D heterobilayer TE materials, owing to its strong Rashba splitting and significant anharmonicity.

Citations

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