论文标题
狄拉克半法的大型异常效应的合理设计
Rational design of large anomalous Nernst effect in Dirac semimetals
论文作者
论文摘要
异常的Nernst效应会产生垂直于温度梯度的横向电压。与能量转化的纵向热电学相比，它具有几个优点，例如电子和热传输的解耦，更高的柔韧性和更简单的横向结构。然而，仍然没有特定材料系统的设计原理，用于获得大型异常的Nernst电导率（ANC）。在这项工作中，我们从理论上证明了Zeeman场下的一对Dirac节点相对于化学势和补偿载体表现出双峰异常的霍尔电导率曲线，从而使Fermi水平固定在Fermi水平上，与两个Weyl Semimimatal相比，它与两个Weyl Nodes相比。然后，基于第一原理计算，我们提供了两个Dirac半准候选者，即Na3bi和Nateau，并表明在Zeeman领域下，它们的ANC值分别显示为0.4 A/（M*K）和1.3 A/（M*K），分别在Fermi水平附近。我们的工作提供了一个设计原理，具有原型带结构，用于增强ANC在费米级别上固定，从而阐明了基于电子结构的其他特定功能材料的逆设计。
Anomalous Nernst effect generates a transverse voltage perpendicular to the temperature gradient. It has several advantages compared with the longitudinal thermoelectricity for energy conversion, such as decoupling of electronic and thermal transports, higher flexibility, and simpler lateral structure. However, a design principle beyond specific materials systems for obtaining a large anomalous Nernst conductivity (ANC) is still absent. In this work, we theoretically demonstrate that a pair of Dirac nodes under a Zeeman field manifests a double-peak anomalous Hall conductivity curve with respect to the chemical potential and a compensated carriers feature, leading to an enhanced ANC pinning at the Fermi level compared with that of a simple Weyl semimetal with two Weyl nodes. Based on first-principles calculations, we then provide two Dirac semimetal candidates, i.e., Na3Bi and NaTeAu, and show that under a Zeeman field they exhibit a sizable ANC value of 0.4 A/(m*K) and 1.3 A/(m*K), respectively, near the Fermi level. Our work provides a design principle with a prototype band structure for enhanced ANC pinning at Fermi level, shedding light on the inverse design of other specific functional materials base on electronic structure.
