Thermoelectric performance of monolayer InSe improved by convergence of multivalley bands
Thermoelectric performance of monolayer InSe improved by convergence of multivalley bands
复制标题
DOI：
10.1063/1.5040752
复制
发表时间：
2019-02-28
影响因子：
3.2
通讯作者：
Saito, Riichiro
中科院分区：
文献类型：
--
作者：
Hung, Nguyen T.;Nugraha, Ahmad R. T.;Saito, Riichiro
我们从理论上研究了通过多谷能带的收敛来提高单层InSe的热电性能的可能性，其中一些明显的谷变得几乎简并。通过施加机械应变来实现能带的会聚。我们发现，单层InSe的热电功率因数可以显着提高了近3倍，通过在两个价（p型）和导（n型）带的带收敛下的双轴压应力约1.16 GPa。然而，p型和n型InSe中的品质因数ZT的最大增强彼此不同，这取决于谷在每种情况下如何收敛。最佳情况是在带会聚中重谷接近轻谷，这将导致功率因数增加，同时电子的热导率降低，这种最佳情况可以在应变n型InSe中得到，其ZT的最大提高高达未应变InSe的230%ZT。相比之下，ZT在应变p型InSe中的增强，其表现出相反的谷收敛（轻谷加入重谷），仅给出未应变InSe的26%ZT。出版社：AIP Publishing
We theoretically investigate a possibility of improving the thermoelectric performance of monolayer InSe through convergence of multivalley energy bands, in which some distinct valleys become almost degenerate. The convergence of energy bands is achieved by applying mechanical strain. We find that the thermoelectric power factor of monolayer InSe can be significantly enhanced by nearly a factor of 3 through the band convergence in both valence (p-type) and conduction (n-type) bands under a biaxial compressive stress of about 1.16 GPa. However, the maximum enhancement of the figure of merit ZT in the p-type and n-type InSe differs each other depending on how the valleys converge in each case. The optimal scenario is that the heavy valleys approach the light valleys in the band convergence, which leads to an increase in the power factor and, at the same time, a decrease in the thermal conductivity of an electron. This optimal condition can be obtained in the strained n-type InSe that gives the largest enhancement of ZT as high as 230% ZT of unstrained InSe. In contrast, the enhancement of ZT in the strained p-type InSe, which exhibits opposite valley convergence (light valleys joining heavy ones), gives only 26% ZT of unstrained InSe. Published by AIP Publishing.