Vector Optical Activity in the Weyl Semimetal TaAs

TL;DR

This paper demonstrates that the Weyl semimetal TaAs exhibits significant vector optical activity due to its topological properties, with ab initio calculations showing a notable polar vector contribution to x-ray diffraction, comparable to linear dichroism effects.

Contribution

It introduces the concept of vector optical activity in Weyl semimetals and quantifies this effect in TaAs using ab initio calculations at the Ta L1 edge.

Findings

Polar vector contribution to optical activity in TaAs is significant.

Resonant x-ray diffraction shows effects comparable to linear dichroism.

Implications for optical phenomena in topological Weyl semimetals are discussed.

Abstract

It is shown that the Weyl semimetal TaAs can have a significant polar vector contribution to its optical activity. This is quantified by ab initio calculations of the resonant x-ray diffraction at the Ta L1 edge. For the Bragg vector (400), this polar vector contribution to the circular intensity differential between left and right polarized x-rays is predicted to be comparable to that arising from linear dichroism. Implications this result has in regards to optical effects predicted for topological Weyl semimetals are discussed.