论文标题
测量热电系数时测量什么？
What is measured when measuring a thermoelectric coefficient?
论文作者
论文摘要
热梯度在任何固体托管移动电子中都会产生电场。在有限磁场（或浆果曲率）的情况下，该电场具有横向分量。这些被称为Seebeck和Nernst系数。正如卡伦（Callen）所说，早在1948年，塞贝克效应量化了在没有热梯度的情况下由带电颗粒流动的熵。同样，$α_{xy} $ $α_{xy} $，在没有热梯度的情况下量化了磁通流的熵。本文总结了一张图片，其中热电响应的粗糙幅度由基本单元和材料依赖的长度尺度给出。因此，对材料依赖性长度尺度的知识允许预测通过实验测量的信号的幅度。具体而言，Nern的电导率与金属中的平均无路径的平方缩放。其在磁铁中的异常分量与虚拟磁长的平方尺度。超级导体的正常状态的短暂库珀对产生信号，该信号与超导相干长度的平方缩放，并平稳地演变为临界温度以下的移动涡流产生的信号。
A thermal gradient generates an electric field in any solid hosting mobile electrons. In presence of a finite magnetic field (or Berry curvature) this electric field has a transverse component. These are known as Seebeck and Nernst coefficients. As Callen argued, back in 1948, the Seebeck effect quantifies the entropy carried by a flow of charged particles in absence of thermal gradient. Similarly, the Nernst conductivity, $α_{xy}$, quantifies the entropy carried by a flow of magnetic flux in absence of thermal gradient. The present paper summarizes a picture in which the rough amplitude of the thermoelectric response is given by fundamental units and material-dependent length scales. Therefore, knowledge of material-dependent length scales allows predicting the amplitude of the signal measured by experiments. Specifically, the Nernst conductivity scales with the square of the mean-free-path in metals. Its anomalous component in magnets scales with the square of the fictitious magnetic length. Ephemeral Cooper pairs in the normal state of a superconductor generate a signal, which scales with the square of the superconducting coherence length and smoothly evolves to the signal produced by mobile vortices below the critical temperature.
