Prediction of Spin Polarized Fermi Arcs in Quasiparticle Interference of CeBi

TL;DR

This paper predicts that CeBi in its ferromagnetic state is a Weyl semimetal with spin-polarized Fermi arcs, and proposes that spin-dependent quasiparticle interference can serve as a fingerprint for Weyl nodes.

Contribution

It provides the first theoretical prediction of Weyl semimetal behavior and spin-polarized Fermi arcs in CeBi, including their detection via spin-polarized ARPES and QPI.

Findings

Two pairs of Weyl nodes are identified near the Fermi level.

Fermi arcs are strongly spin-polarized in opposite directions.

Spin-dependent QPI reveals bifurcation features linked to Weyl nodes.

Abstract

We predict that CeBi in the ferromagnetic state is a Weyl semimetal. Our calculations within density functional theory show the existence of two pairs of Weyl nodes on the momentum path $(0, 0, k_z)$ at $15$ meV} above and $100$ meV below the Fermi level. Two corresponding Fermi arcs are obtained on surfaces of mirror-symmetric (010)-oriented slabs at $E=15$ meV and both arcs are interrupted into three segments due to hybridization with a set of trivial surface bands. By studying the spin texture of surface states, we find the two Fermi arcs are strongly spin-polarized but in opposite directions, which can be detected by spin-polarized ARPES measurements. Our theoretical study of quasiparticle interference (QPI) for a nonmagnetic impurity at the Bi site also reveals several features related to the Fermi arcs. Specifically, we predict that the spin polarization of the Fermi arcs leads to a bifurcation-shaped feature only in the spin-dependent QPI spectrum, serving as a fingerprint of the Weyl nodes.