Phonon thermal transport in Janus single layer M_{2}XY (M = Ga; X, Y = S, Se, Te): A study based on firstprinciples
Abstract
Based on the firstprinciples calculations, we introduced several stable 2D Janus single layer materials (Ga_{2}SSe, Ga_{2}STe, Ga_{2}SeTe) and carried out a series of thermal transport studies of them. Ga_{2}STe and Ga_{2}SeTe are belong to the direct bandgap semiconductors while the Ga_{2}SSe is indirect bandgap semiconductor. The calculated lattice thermal conductivity κ_{L} is arranged in the sequence of Ga_{2}SSe > Ga_{2}SeTe > Ga_{2}STe, and in the room temperature the corresponding values are 26.16 W m^{1} K ^{1}, 11.98 W m^{1} K ^{1} and 15.72 W m^{1} K ^{1} for monolayer Ga_{2}SSe, Ga_{2}STe and Ga_{2}SeTe, respectively, the optical modes have the smallest contributions to the lattice thermal conductivity. For the purpose of application in the thermoelectric field, which can be further reduced by adjust sample size appropriately. Ga_{2}STe has a similar phonon group velocity with Ga_{2}SeTe, the larger scattering rates caused the smaller lattice thermal conductivity of it. By studying the thermal transport of different phonon modes we found an unusual relationship between the anharmonic scattering rates and the weighted phase space W. The above researches demonstrate a range of thermoelectric properties of these 2D Janus single layer materials and lay the foundation for their better applications in the thermoelectric field.
 Publication:

Physica E LowDimensional Systems and Nanostructures
 Pub Date:
 January 2020
 DOI:
 10.1016/j.physe.2019.113683
 Bibcode:
 2020PhyE..11513683Z
 Keywords:

 Janus single layer materials;
 Firstprinciples calculations;
 Lattice thermal conductivity;
 Anharmonic scattering rates