单层BiSbTeSe_(2)热电性能的第一性原理研究

First-Principles Study on Thermoelectric Properties of Monolayer BiSbTeSe_(2)

本文利用第一性原理计算并结合玻尔兹曼输运方程,预测了一种热电性能优良的新型Bi_(2)Te_(3)基材料,即单层BiSbTeSe_(2)。通过系统计算单层BiSbTeSe_(2)的电子能带结构和热电输运性质,发现单层BiSbTeSe_(2)在300 K时的塞贝克系数达到最高值(522μV·K^(-1)),在500 K时功率因子与弛豫时间的比值最大为5.78 W·m^(-1)·K^(-2)·s^(-1)。除此之外,单层BiSbTeSe_(2)还具有较低的晶格热导率和较高的迁移率。在最佳p型掺杂下,单层BiSbTeSe_(2)在500 K时的热电优值ZT高达3.95。单层BiSbTeSe_(2)的优良性能表明其在300~500 K的中温热电器件领域具有潜在的应用价值,可以为进一步开发高性能Bi_(2)Te_(3)基热电材料提供设计依据。

Based on the first-principles calculation and Boltzmann transport equation,a new Bi_(2)Te_(3)-based material with excellent thermoelectric properties,namely monolayer BiSbTeSe_(2),is predicted.By systematically calculating the electronic band structure and thermoelectric transport properties of monolayer BiSbTeSe_(2),it is found that the maximum Seebeck coefficient of monolayer BiSbTeSe_(2)reaches the highest value(522μV·K^(-1))at 300 K,and the maximum ratio of power factor to relaxation time at 500 K is 5.78 W·m^(-1)·K^(-2)·s^(-1).In addition,the monolayer BiSbTeSe_(2)has lower lattice thermal conductivity and higher mobility.Under the optimum p-type doping,the thermoelectric figure of merit ZT of monolayer BiSbTeSe_(2)at 500 K is as high as 3.95.The excellent performance of monolayer BiSbTeSe_(2)shows that it has potential application value in the field of medium-temperature electrical devices in the temperature range of 300~500 K,which can provide design basis for further developing high-performance Bi_(2)Te_(3)-based thermoelectric materials.