Higher-order double-Weyl semimetal in Stacked two-dimensional Su-Schrieffer-Heeger lattice

Abstract Higher-order Weyl semimetals (HOWSMs) with coexisting Fermi arc and hinge states establish a fundamental connection between Weyl physics and higher-order topology. In this work, we theoretically propose the higher-order double-Weyl semimetals (HODWSMs) in a stacked SSH lattice with helical interlayer coupling. The system hosts four quadratic double-Weyl points (charges ±2) at k z = 0, ± π . In every other k z plane the effective two-dimensional subsystem simultaneously exhibits a nonzero Chern number and a nontrivial Z 4 Berry phase, supporting Fermi arcs and gapless hinge states that span the entire Brillouin zone. This work extends the research scope of HOWSMs and offers a new platform for exploring higher-order Weyl physics.