论文标题
Janusα-Ste2和α-SETE2单层的超高热电性能
Ultrahigh thermoelectric performance of Janus α-STe2 and α-SeTe2 monolayers
论文作者
论文摘要
结合第一原理的计算和半经典的玻尔兹曼传输理论，Janusα-STE2和α-SETE2单层的单层被系统地研究。 Janusα-STE2和α-SETE2单层是间接半导体，带隙为1.20和0.96 eV。发现它们具有500 K时的超高功绩（ZT）值为3.9和4.4，远高于原始α-TE单层的值（2.8）。较高的ZT起源于Janus结构，与原始的α-TE单层相比，降低了晶格的热电导率。 Janus单层中高得多的声子非谐度导致晶格的显着较低的导热率。还发现电子热导率可以在晶状体导热率相当低的材料的热电效率中发挥重要作用。这项工作表明，Janusα-STE2和α-SETE2单层作为热电材料的潜在应用，并突出显示Janus结构是增强热电性能的有效方法。
Combined with first-principles calculations and semiclassical Boltzmann transport theory, Janus α-STe2 and α-SeTe2 monolayers are investigated systematically. Janus α-STe2 and α-SeTe2 monolayers are indirect semiconductors with band gaps of 1.20 and 0.96 eV. It is found they possess ultrahigh figure of merit (ZT) values of 3.9 and 4.4 at 500 K, much higher than that of the pristine α-Te monolayer (2.8). The higher ZT originates from Janus structures reduce lattice thermal conductivities remarkably compared with pristine α-Te monolayer. The much higher phonon anharmonicity in Janus monolayers leads to significant lower lattice thermal conductivity. It is also found electronic thermal conductivity can play an important role in thermoelectric efficiency for the materials with quite low lattice thermal conductivity. This work suggests the potential applications of Janus α-STe2 and α-SeTe2 monolayers as thermoelectric materials and highlights Janus structure as an effective way to enhance thermoelectric performance.
