Weyl Fermion with various chiralities in a f-electron ferromagnetic system: PrB4

TL;DR

This paper predicts that ferromagnetic PrB4 hosts multiple Weyl fermions with large Fermi-arc surface states and significant anomalous Hall conductivity, making it a promising candidate for spintronic and photonic applications.

Contribution

It is the first theoretical study revealing PrB4 as an intrinsic magnetic Weyl system with multiple topological band crossings and large surface states.

Findings

PrB4 hosts multiple Weyl points with various chiral charges.

Large Fermi-arc surface states are present in PrB4.

Anomalous Hall conductivity is estimated to be 500-1000 (Ω·cm)^-1.

Abstract

Rare-earth tetraborides ($R$B$_{4}$) have attracted a lot of recent attention due to their intriguing electronic, magnetic, and topological properties. We have theoretically investigated topological properties of PrB$_{4}$, which is unique among $R$B$_{4}$ family due to its ferromagnetic ground state. We have discovered that PrB$_{4}$ is an intrinsic magnetic Weyl system possessing multiple topological band crossings with various chiral charges. Density-functional-theory band calculations combined with tight-binding band analysis reveal large Fermi-arc surface states, which are characteristic fingerprints of Weyl fermions. Anomalous Hall conductivity is estimated to be very large, ranging from 500 to 1000 ($\Omega \cdot$cm)$^{-1}$ near the Fermi level, which also demonstrates the topological Weyl character of ferromagnetic PrB$_{4}$. These findings suggest that PrB$_{4}$, being a potential candidate of magnetic Weyl system, would be a promising rare-earth topological system for applications to next-generation spintronic and photonic devices.