Enhanced power factor and reduced Lorenz number in the Wiedemann–Franz law due to pudding mold type band structures
Enhanced power factor and reduced Lorenz number in the Wiedemann–Franz law due to pudding mold type band structures
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DOI：
10.1063/1.4981890
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发表时间：
2016-12
影响因子：
3.2
通讯作者：
H. Usui;K. Kuroki
中科院分区：
文献类型：
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作者：
H. Usui;K. Kuroki
我们研究了电子能带结构的形状和热电性能之间的关系。为了研究热电性质的能带形状依赖性，我们首先采用具有色散E（k）=| K| n，其中n = 2、4和6。我们考虑一维，二维和三维系统和计算的热电性能使用玻尔兹曼方程的方法内的恒定准粒子寿命近似。n = 2对应于通常的抛物线能带结构，而n = 4和6的能带形状在能带边缘具有平坦部分，使得态密度在能带底部发散。我们称这种带结构为“布丁型带”。n ≥ 4属于布丁模型带，但由于在一维系统中即使n = 2，态密度也发散，因此也将其归类为布丁模型。由于大的态密度和群速度的快速变化，
We study the relationship between the shape of the electronic band structure and the thermoelectric properties. In order to study the band shape dependence of the thermoelectric properties generally, we first adopt models with band structures having the dispersion E ( k ) ∼ | k | n with n = 2, 4, and 6. We consider one-, two-, and three-dimensional systems and calculate the thermoelectric properties using the Boltzmann equation approach within the constant quasi-particle lifetime approximation. n = 2 corresponds to the usual parabolic band structure, while the band shape for n = 4 and 6 has a flat portion at the band edge, so that the density of states diverges at the bottom of the band. We call this kind of band structure the “pudding mold type band”. n ≥ 4 belong to the pudding mold type band, but since the density of states diverges even for n = 2 in the one dimensional system, this is also categorized as the pudding mold type. Due to the large density of states and the rapid change of the group veloci...