Quantum mechanics

Theoretical physics

Phase (matter)

Topological quantum number

Economics

Band gap

Chiral anomaly

Physics

Mathematics

Fermion

Semimetal

Tetragonal crystal system

Condensed matter physics

Combinatorics

Finance

Topology (electrical circuits)

Order (exchange)

Fermi Gamma-ray Space Telescope

Weyl semimetal

Physical Review Letters

Higher-order topology yields intriguing multidimensional topological phenomena, while Weyl semimetals have unconventional properties such as chiral anomaly. However, so far, Weyl physics remain disconnected with higher-order topology. Here, we report the theoretical discovery of higher-order Weyl semimetals and thereby the establishment of such an important connection. We demonstrate that higher-order Weyl semimetals can emerge in chiral materials such as chiral tetragonal crystals as the intermediate phase between the conventional Weyl semimetal and 3D higher-order topological phases. Higher-order Weyl semimetals manifest themselves uniquely by exhibiting concurrent chiral Fermi-arc surface states, topological hinge states, and the momentum-dependent fractional hinge charge, revealing a novel class of higher-order topological phases.

Higher-Order Weyl Semimetals