Optimal band gap for improved thermoelectric performance of two-dimensional Dirac materials
Abstract
Thermoelectric properties of two-dimensional (2D) Dirac materials are calculated within linearized Boltzmann transport theory and relaxation time approximation. We find that the gapless 2D Dirac material exhibits poorer thermoelectric performance than the gapped one. Furthermore, there exists an optimal band gap for maximizing the figure of merit (ZT) in the gapped 2D Dirac material. The optimal band gap ranges from 6kBT to 18kBT, where kB is the Boltzmann constant and T is the operating temperature in kelvin. This result, which is similar to that for bulk semiconductors, indicates the importance of having narrow gaps to achieve the best thermoelectrics in 2D systems. Larger maximum ZTs can also be obtained by suppressing the lattice thermal conductivity. In the most ideal case where the lattice thermal conductivity is zero (leaving the electron thermal conductivity alone), the maximum ZT in the gapped 2D Dirac material is many times ZT of commercial thermoelectric materials.
Keywords
Cite
@article{arxiv.1901.03999,
title = {Optimal band gap for improved thermoelectric performance of two-dimensional Dirac materials},
author = {Eddwi H. Hasdeo and Lukas P. A. Krisna and Muhammad Y. Hanna and Bobby E. Gunara and Nguyen T. Hung and Ahmad. R. T. Nugraha},
journal= {arXiv preprint arXiv:1901.03999},
year = {2019}
}
Comments
10 pages, 11 figures, accepted to Jour. Appl. Physics