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arXiv 1111.5355cond-mat.mtrl-sci
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低有效质量导致高热电性能

Low Effective Mass Leading to High Thermoelectric Performance

Yanzhong Pei, Aaron D. LaLonde, Heng Wang, G. Jeffrey Snyder

摘要:

通过电子结构修饰或操纵纳米结构在费米能级附近产生大的态密度(DOS)来获得高塞贝克系数通常被认为是实现先进热电器件的途径。然而,大的态密度,由于平坦的能带导致大的有效质量,这导致在迁移率的同时下降。实际上,根据Bardeen-Shockley的变形势理论,当载流子主要由声学声子散射时,高有效质量的净效应是较低的热电优值。我们证明了轻的有效质量的有益效果,导致高功率因数的n型热电碲化铅,掺杂和温度可以用来调整的有效质量。这清楚地证明了变形势理论对热电的指导原则,能带结构工程应沿输运方向的低有效质量。

英文摘要:

High Seebeck coefficient by creating large density of state (DOS) around the Fermi level through either electronic structure modification or manipulating nanostructures, is commonly considered as a route to advanced thermoelectrics. However, large density of state due to flat bands leads to large effective mass, which results in a simultaneous decrease of mobility. In fact, the net effect of high effective mass is a lower thermoelectric figure of merit when the carriers are predominantly scattered by acoustic phonons according to the deformation potential theory of Bardeen-Shockley. We demonstrate the beneficial effect of light effective mass leading to high power factor in n-type thermoelectric PbTe, where doping and temperature can be used to tune the effective mass. This clear demonstration of the deformation potential theory to thermoelectrics shows that the guiding principle for band structure engineering should be low effective mass along the transport direction.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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