Impressive Electronic Transport in Be${}_2$C Monolayer

Abstract

We present thermoelectric properties of Be${}_2$C monolayer based on density functional theory and semi-classical Boltzmann transport theory. Electronic structure calculations predict this material as a semiconductor with a direct bandgap of 2.0 eV computed using Gaussian-attenuating Perdew-Burke-Ernzerhof (Gau-PBE) hybrid functional. The Gau-PBE band structure is used to compute transport properties by solving the Boltzmann transport equation under the constant relaxation time approximation. In this work, we have explicitly determined the relaxation time by studying the electron-phonon interactions in the system to estimate absolute transport coefficients. Our results show that the monolayer possesses a high power factor ($\sim$ 3.44 mW/mK${}^2$ @300K), similar to the commercial TE materials doped-Bi${}_2$Te${}_3$ and PbTe, suggesting that Be${}_2$C monolayer is a promising thermoelectric material.

19 pages, 7 figures