论文标题
狭窄的间隙材料中的超高热电功率因子具有不对称带
Ultra-High Thermoelectric Power Factors in Narrow Gap Materials with Asymmetric Bands
论文作者
论文摘要
从理论上讲，我们在双极传输方案中以不对称传导/价频段进行的，在轻度掺杂的狭窄间隙半导体中实现极高的热电功率因子的非常规的可能性。具体而言，使用Boltzmann的传输模拟，我们表明，如果在有效的质量，状态的密度，或者声子散射速率方面，则狭窄的带隙材料，而不是由于双极传导而遭受性能降解，那么它们可以提供很高的功率因子。我们表明，这是因为在这些条件下，电子传输变成了声子散射有限，而不是电离杂质散射有限，这允许大电导率。我们解释了为什么迄今未在已知的狭窄差异半导体中观察到这种效果，解释了一些最近相关的实验发现，并提出了一些可以观察到的效果的示例，甚至可以达到50 mw/m $ k^2 $。
We theoretically unveil the unconventional possibility to achieve extremely high thermoelectric power factors in lightly doped narrow gap semiconductors with asymmetric conduction/valence bands operated in the bipolar transport regime. Specifically, using Boltzmann transport simulations, we show that narrow bandgap materials, rather than suffering from performance degradation due to bipolar conduction, if they possess highly asymmetric conduction and valence bands in terms of either effective masses, density of states, or phonon scattering rates, then they can deliver very high power factors. We show that this is reached because, under these conditions, electronic transport becomes phonon scattering limited, rather than ionized impurity scattering limited, which allows large conductivities. We explain why this effect has not been observed so far in the known narrow-gap semiconductors, interpret some recent related experimental findings, and propose a few examples from the half-Heusler materials family for which this effect can be observed and power factors even up to 50 mW/m$K^2$ can be reached.
