Tunning lattice thermal conductivity of bilayer and trilayer molybdenum disulfide thermoelectric materials through twist angles

Exploring approaches to reduce lattice thermal conductivity is effective to improve the performance of molybdenum disulfide thermoelectric materials, and tuning lattice thermal conductivity via twist angles attracts increasing attention. However, few studies focused on the effects of twist angle on lattice thermal conductivity of molybdenum disulfide thermoelectric materials, particularly, the coupling effects of two twist angles on lattice thermal conductivity of tri-layer molybdenum disulfide. In this work, the effects of twist angles on lattice thermal conductivity of twisted bilayer and trilayer molybdenum disulfide were investigated by molecular dynamics simulation. Phonon dispersion was calculated through density functional theory to provide a deeper understanding of thermal conduction. The results indicated that for the twisted bilayer sample, the relationship between thermal conductivity and twist angle exhibits Wshaped, and the minimum thermal conductivity can be obtained with the twist angle of 15 degrees The phonon analyses indicated that the twist angle has a significant effect on ZA branches, and the effects of the twist angle on group velocities and phonon lifetime of LA and TA branches contribute to the change of thermal conductivity. As for the twisted tri-layer sample, the minimum thermal conductivity can be obtained when the sum of two twist angles is an odd multiple of 15 degrees, which is recommended for thermoelectric materials design. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the effects of twist angles on the lattice thermal conductivity of molybdenum disulfide in twisted bilayer and trilayer configurations. The results show that in the twisted bilayer sample, the thermal conductivity exhibits a W-shaped relationship with the twist angle, and the minimum thermal conductivity is achieved at a twist angle of 15 degrees. For the twisted trilayer sample, the minimum thermal conductivity is obtained when the sum of the two twist angles is an odd multiple of 15 degrees. These findings provide valuable insights for the design of thermoelectric materials.