新型热电材料Y_(2)Te_(3)热电性能应变调控研究

Thermoelectric Properties of the Novel Thermoelectric Material Y_(2)Te_(3) Through Strain Modulation

具有低晶格热导率的稀土硫族化合物Y_(2)Te_(3)是一种非常有前途的新型热电材料,施加应变是调控热电材料热电性能的有效手段。本文采用第一性原理方法结合半经典玻尔兹曼输运理论,通过施加-4%到4%的应变对Y_(2)Te_(3)材料的热电性能进行应变调控。研究表明,施加压缩应变对Y_(2)Te_(3)材料热电性能的提高优于施加拉伸应变。300 K下p型Y_(2)Te_(3)的最大功率因数由0.4 mW·m^(-1)·K-2提升到1.6 mW·m^(-1)·K-2,n型Y_(2)Te_(3)在压缩应变下最大功率因数由8 mW·m^(-1)·K^(-2)提升到11 mW·m^(-1)·K^(-2)。300 K下p型Y_(2)Te_(3)在应变调控下最大热电优值ZT由0.07提升到0.15,n型Y_(2)Te_(3)在压缩应变下最大热电优值ZT由0.7提升到0.9。因此,n型Y_(2)Te_(3)具有非常优异的热电性能,通过施加应变可以有效调控Y_(2)Te_(3)材料的热电性能,n型Y_(2)Te_(3)具有作为热电材料的巨大潜力。

The rare-earth chalcogenides Y_(2)Te_(3)with low lattice thermal conductivity is a very promising novel thermoelectric material.Applying strain is an effective way to modulate the thermoelectric properties of thermoelectric materials.In this paper,first-principles approach combined with the semiclassical Boltzmann transport theory were used to study the strain modulation of the thermoelectric properties of Y_(2)Te_(3)materials,for which-4%to 4%strain was applied to the Y_(2)Te_(3)materials.The results show that applying compressive strain may modulate thermoelectric properties more effectively than tensile strain.The maximum power factor of p-type Y_(2)Te_(3)increases from 0.4 mW·m^(-1)·K^(-2) to 1.6 mW·m^(-1)·K^(-2) at 300 K,and the maximum power factor of n-type Y_(2)Te_(3)increases from 8 mW·m^(-1)·K^(-2) to 11 mW·m^(-1)·K^(-2) under compressive strain.The maximum thermoelectric figure of merit(ZT)of p-type Y_(2)Te_(3)increases from 0.07 to 0.15 under strain modulation at 300 K,and the maximum ZT of n-type Y_(2)Te_(3)increases from 0.7 to 0.9 under compressive strain.Therefore,n-type Y_(2)Te_(3)has very excellent thermoelectric properties,and the thermoelectric properties of Y_(2)Te_(3)materials can be effectively regulated by applying strain.n-type Y_(2)Te_(3)has great potential as a thermoelectric material.