Abstract
Abstract
Unlike graphene-like silicene, a recently reported hybrid honeycomb-kagome (hhk) silicene is a semiconductor instead of a gapless Dirac-cone, which has great potential applications in semiconducting devices. Here, using first-principles calculations combined with Boltzmann transport equation, we find that hhk-silicene has high Seebeck coefficient and power factor as arising from the moderate band-gap and low effective mass. Meanwhile, compared to graphene-like silicene, the soften acoustic branches and enhanced anharmonicity lead to the extremely low lattice thermal conductivity, i.e., 0.68 W mK−1 at 300 K. Calculated thermoelectric figure of merit reaches 1.98 at 300 K, which is a recorded value among two-dimensional materials, indicating the potential of hhk-silicene as a thermoelectric material.
Funder
National Natural Science Foundation of China
Department of Science and Technology, Hubei Provincial People's Government
Chongqing Municipal Education Commission Foundation
Subject
Condensed Matter Physics,Mathematical Physics,Atomic and Molecular Physics, and Optics