Helical Fermi Arc in Altermagnetic Weyl Semimetal

TL;DR

This paper introduces a new mechanism for creating altermagnetic Weyl semimetals using an altermagnetic mass term, leading to unique coexisting helical Fermi arcs and Weyl nodes, with potential experimental realization in multilayer structures.

Contribution

It presents a novel theoretical framework for altermagnetic Weyl semimetals driven by an altermagnetic mass term, including a minimal lattice model and a practical realization scheme.

Findings

Revealed a new mechanism for Weyl semimetals via altermagnetic mass

Constructed a minimal 3D lattice model with coexisting helical Fermi arcs

Proposed a multilayer structure for experimental realization

Abstract

We investigate the topological properties of modified Dirac Hamiltonians with an altermagnetic mass term and reveal a novel mechanism for realizing altermagnetic Weyl semimetals. Unlike the conventional Wilson mass, the altermagnetic mass drives direct transitions between nontrivial Chern phases of opposite sign and fundamentally reshapes the band inversion surface. By extending this framework to three dimensions, we construct a minimal lattice model that hosts pairs of Weyl nodes as well as coexisting helical Fermi arcs with opposite chirality on the same surface, which is a phenomenon not found in conventional magnetic Weyl semimetals. We further propose a practical scheme to realize these phases in multilayer structures of 2-dimensional Rashba metal with engineered $d$-wave altermagnetic order. Our results deepen the theoretical understanding of mass terms in Dirac systems and provide concrete guidelines for the experimental detection and realization of altermagnetic Weyl semimetals.