Multiple types of spin textures and robust valley physics in MP$_2$X$_6$

TL;DR

This study reveals that SnP$_{2}$Se$_{6}$ monolayer hosts multiple spin textures and valley-dependent electronic properties, offering new opportunities for spintronics and valleytronics applications through first-principles calculations.

Contribution

It demonstrates the coexistence of Weyl-type and Ising-type spin textures in a single material, linking spin textures with valley degrees of freedom for the first time.

Findings

Presence of Weyl-type and Ising-type spin textures at different valleys.

Valley-dependent Berry-curvature-driven anomalous Hall currents.

Optical selectivity varies with valley in SnP$_{2}$Se$_{6}$ monolayer.

Abstract

Both spin textures and multiple valleys in the momentum space have attracted great attentions due to their versatile applications in spintronics and valleytronics. It is highly desirable to realize multiple types of spin textures in a single material and further couple the spin textures to valley degree of freedom. Here, we study electronic properties of SnP$_{2}$Se$_{6}$ monolayer by first-principles calculations. The monolayer exhibits rare Weyl-type and Ising-type spin textures at different valleys, which can be conveniently expressed by electron and hole dopings, respectively. Besides valley-contrasting spin textures, Berry-curvature-driven anomalous Hall currents and optical selectivity are found to be valley dependent as well. These valley-related properties also have generalizations to SnP$_{2}$Se$_{6}$ few-layers and other MP$_{2}$X$_{6}$. Our findings open new avenue for exploring appealing interplay between spin textures and multiple valleys, and designing advanced device paradigms based on spin and valley degrees of freedom.