Potential 2D thermoelectric materials ATeI (A=Sb and Bi) monolayers from a first-principles study

Abstract

Lots of two-dimensional (2D) materials have been predicted theoretically, and further confirmed in experiment, which have wide applications in nanoscale electronic, optoelectronic and thermoelectric devices. Here, the thermoelectric properties of ATeI (A=Sb and Bi) monolayers are systematically investigated, based on semiclassical Boltzmann transport theory. It is found that spin-orbit coupling (SOC) has important effects on electronic transport coefficients in p-type doping, but neglectful influences on n-type ones. The room-temperature sheet thermal conductance is 14.2 $\mathrm{W}{\mathrm{K}}^{-1}$ for SbTeI and 12.6 $\mathrm{W}{\mathrm{K}}^{-1}$ for BiTeI, which are lower than one of most well-known 2D materials, such as transition-metal dichalcogenide, group IV-VI, group-VA and group-IV monolayers. By analyzing group velocities and phonon lifetimes, the very low sheet thermal conductance of ATeI (A=Sb and Bi) monolayers is mainly due to small group velocities. It is found that the high-frequency optical branches contribute significantly to the total thermal conductivity, being obviously different from usual picture with little contribution from optical branches. According to cumulative lattice thermal conductivity with respect to phonon mean free path (MFP), it is difficulty to further reduce lattice thermal conductivity by nanostructures. Finally, possible thermoelectric figure of merit $ZT$ of ATeI (A=Sb and Bi) monolayers are calculated. It is found that the p-type doping has more excellent thermoelectric properties than n-type doping, and at room temperature, the peak $ZT$ can reach 1.11 for SbTeI and 0.87 for BiTeI, respectively. These results make us believe that ATeI (A=Sb and Bi) monolayers may be potential 2D thermoelectric materials, and can stimulate further experimental works to synthesize these monolayers.

8 pages, 11 figures. arXiv admin note: text overlap with arXiv:1701.08944

References in corpus (7)

• BoltzTraP. A code for calculating band-structure dependent quantities
• Distribution of phonon lifetime in Brillouin zone
• Large Thermoelectricity via Variable Range Hopping in Chemical Vapor Deposition Grown Single-layer MoS2
• Unexpected phonon-transport properties of stanene among 2D group-IV materials from \textit{ab initio}
• How to Characterize Thermal Transport Capability of 2D Materials Fairly? - Sheet Thermal Conductance and the Choice of Thickness
• Thermoelectric properties of orthorhombic group IV-VI monolayers from the first-principles calculations
• Thermoelectric properties of $\beta$-As, Sb and Bi monolayers

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