论文标题
狭窄差距半导体中Nernst效应异常温度依赖性的起源
Origin of anomalous temperature dependence of Nernst effect in narrow-gap semiconductors
论文作者
论文摘要
基于Boltzmann运输理论，我们研究了由于声子 - 拖拉机制而导致的Nernst系数（$ν$）的异常温度依赖性的起源。对于狭窄的半导体，我们发现有两个特征温度，其中明显的峰结构以$ν$出现。相反，Seebeck系数（$ S $）总是只有一个峰。尽管由于电子松弛时间的动量依赖性而导致的Sondheimer取消的崩溃对于低$ t $以$ν$的峰值至关重要，但价波段对声子拖拉电流的贡献对于较高$ t $的峰值至关重要。通过考虑这种机制，我们成功地复制了$ν$和FESB $ _2 $的$ S $，用于实验观察到巨大的声子效果。
Based on the Boltzmann transport theory, we study the origin of the anomalous temperature dependence of the Nernst coefficient ($ν$) due to the phonon-drag mechanism. For narrow-gap semiconductors, we find that there are two characteristic temperatures at which a noticeable peak structure appears in $ν$. Contrarily, the Seebeck coefficient ($S$) always has only one peak. While the breakdown of the Sondheimer cancellation due to the momentum-dependence of the electron relaxation time is essential for the peak in $ν$ at low $T$, the contribution of the valence band to the phonon-drag current is essential for the peak at higher $T$. By considering this mechanism, we successfully reproduce $ν$ and $S$ of FeSb$_2$ for which a gigantic phonon-drag effect is observed experimentally.
