Electronic Properties of the Weyl Semimetals Co2MnX (X=Si, Ge, Sn)

Using first-principles electronic structure calculations, it is shown that ferromagnetic Heusler compounds Co2MnX (X = Si, Ge, Sn) present nontrivial topological characteristics and belong to the category of Weyl semimetals. These materials exhibit two topologically interesting band crossings near the Fermi level. These band crossings have complex 3D geometries in the Brillouin zone and are characterized by nontrivial topology as Hopf links and chain-like nodal lines that are protected by the perpendicular mirror planes. The spin-orbit interaction split these nodal lines into several 0D Weyl band crossings. Unlike previously known topologically nontrivial Heusler materials, these majority spin band crossings lie in or very near to the bandgap of minority spin bands, potentially facilitating experimental observation.

Automated summary

Using first-principles electronic structure calculations, it is shown that ferromagnetic Heusler compounds Co2MnX (X = Si, Ge, Sn) exhibit nontrivial topological characteristics and belong to the category of Weyl semimetals. These materials have two interesting band crossings near the Fermi level, characterized by topological features such as Hopf links and chain-like nodal lines protected by mirror planes.