Valley polarization generated in 3-dimensional group-IV monochalcogenids

TL;DR

This paper demonstrates the generation of valley polarization in 3D group-IV monochalcogenids using optical methods, opening new avenues for valleytronics and device applications.

Contribution

It reports the first successful generation of valley polarization in a 3D system, combining theoretical and experimental techniques.

Findings

Valleys with opposite optical absorption identified in 3D materials.

Valley polarization achieved in 3D system with linearly polarized light.

Strain tuning modulates valley properties in GeSe.

Abstract

Valleytronics is one of the breaking-through to the technology of electronics, which provides a new degree of freedom to manipulate the properties of electrons. Combining DFT calculations, optical absorption analysis and the linear polarization-resolved transmission measurement together, we report that three pairs of valleys, which feature opposite optical absorption, existing in the 3-dimensional (3D) group-IV monochalcogenids. By applying the linearly-polarized light, valley polarization is successfully generated for the first time in a 3D system, which opens a new direction for the exploration of the valley materials and provides a good platform for the photodetector and valleytronic devices. Valley modulation versus the in-plane strain in GeSe is also studied, suggesting an effective way to get the optimized valleytronic properties.