Topology-transport correspondence in silicene under the modulation of electric and antiferromagnetic fields

College of Physics Science and Technology, Yangzhou University - Yangzhou 225002, China

^(a) yfxu@yzu.edu.cn (corresponding author)

Received: 27 July 2020
Accepted: 23 October 2020

Abstract

The low-buckled material silicene undergoes abundant topological phase transitions under external fields. The applications in transport related to the topological properties remain the focus of attention. Utilizing the Berry curvature formula and Boltzmann transport equation, we investigate the spin- and valley-dependent anomalous Nernst effect in silicene, which is subjected to the antiferromagnetic field and perpendicular electric field. The results reveal that the antiferromagnetic field can be used to modulate the pure spin Nernst current; the pure valley Nernst current appears only when electric field exists; the charge Nernst current needs both fields. It is found that the inflection points on the Nernst conductivity correspond exactly to the phase transformation boundary. In the quantum spin Hall (QSH) phase, the spin beam splitting can be realized, in the quantum valley Hall (QVH) phase, the valley beam is split, and in the spin-polarized quantum anomalous Hall (SQAH) phase, the single spin and valley beam can be collected. These findings related to topology are expected to facilitate some applications in spin and valley caloritronics and thermal logical devices.