Weyl and Dirac semimetals are three-dimensional phases of matter with gapless electronic
excitations that are protected by topology and symmetry. As three-dimensional analogs of …

Magnonics addresses the dynamic excitations of a magnetically ordered material. These
excitations, referred to as spin waves and their quanta, magnons, are a powerful tool for …

At sufficiently low temperatures, magnetic materials often enter correlated phases hosting
collective, coherent magnetic excitations such as magnons or triplons. Drawing on the …

In two-dimensional honeycomb ferromagnets, bosonic magnon quasiparticles (spin waves)
may either behave as massless Dirac fermions or form topologically protected edge states …

Pursuing topological phases in natural and artificial materials is one of the central topics in
modern physical science and engineering. In classical magnetic systems, spin waves (or …

We report the discovery of topological magnetism in the candidate magnetic Weyl semimetal
CeAlGe. Using neutron scattering we find this system to host several incommensurate …

By using ab initio calculations and symmetry analysis, we define a class of Weyl phonons:
charge-four Weyl phonons (CFWPs) characterized by Chern number±4 in their acoustic …

Topological semimetal states having the minimal number, ie, only a single pair, of Weyl
points are desirable for the study of effects associated with chiral topological charges. So far …

Condensed matter systems admit topological collective excitations above a trivial ground
state, an example being Chern insulators formed by Dirac bosons with a gap at finite …

Topological magnons are bosonic analogues of topological fermions in electronic systems.
They have been studied extensively by theory but rarely realized by experiment. Here, by …