School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
Sino-Danish Center for Education and Research, Beijing 100190, China.
Phys Rev Lett. 2015 Dec 11;115(24):246601. doi: 10.1103/PhysRevLett.115.246601. Epub 2015 Dec 8.
The spin and valley-dependent anomalous Nernst effects are analyzed for monolayer MoS_{2} and other group-VI dichalcogenides. We find that pure spin and valley currents can be generated perpendicular to the applied thermal gradient in the plane of these two-dimensional materials. This effect provides a versatile platform for applications of spin caloritronics. A spin current purity factor is introduced to quantify this effect. When time reversal symmetry is violated, e.g., two-dimensional materials on an insulating magnetic substrate, a dip-peak feature appears for the total Nernst coefficient. For the dip state it is found that carriers with only one spin and from one valley are driven by the temperature gradient.
我们分析了单层 MoS_{2} 和其他 VI 族二维材料的自旋和谷依赖反常聂耳斯效应。我们发现,在这些二维材料的平面内,垂直于外加热梯度可以产生纯自旋和谷电流。这种效应为自旋热电子学的应用提供了一个通用的平台。我们引入了自旋电流纯度因子来量化这种效应。当时间反转对称性被破坏时,例如在绝缘磁性衬底上的二维材料,总聂耳斯系数会出现一个峰谷特征。对于谷态,我们发现只有一个自旋和一个谷的载流子会受到温度梯度的驱动。