Observation of Fermi arc spin texture in TaAs

TL;DR

This paper reports the experimental observation of spin-polarized Fermi arcs in the Weyl semimetal TaAs, confirming its topologically nontrivial state through spin-resolved photoemission and theoretical calculations.

Contribution

First direct measurement of the spin texture of Fermi arcs in TaAs, validating theoretical predictions and confirming the Weyl semimetal topological state.

Findings

Fermi arcs are spin-polarized

Spin texture matches symmetry requirements

Experimental results agree with first-principles calculations

Abstract

We have investigated the spin texture of surface Fermi arcs in the recently discovered Weyl semimetal TaAs using spin- and angle-resolved photoemission spectroscopy. The experimental results demonstrate that the Fermi arcs are spin-polarized. The measured spin texture fulfills the requirement of mirror and time reversal symmetries and is well reproduced by our first-principles calculations, which gives strong evidence for the topologically nontrivial Weyl semimetal state in TaAs. The consistency between the experimental and calculated results further confirms the distribution of chirality of the Weyl nodes determined by first-principles calculations.