Half-metallic Ferromagnets, Spin Gapless Semiconductors, and Topological Semimetals Based on Heusler Alloys

A review of theoretical and experimental studies of the electronic structure, electronic and magnetic properties of various systems of Heusler alloys in the states of a half-metallic ferromagnet, a spin gapless semiconductor, and a topological semimetal is presented. These substances have unusual, highly sensitive to external influences, magnetic and electronic characteristics, which is associated with the presence of energy gaps and exotic excitations in them. The features of the behavior and evolution of the electronic structure and properties in each of these states, as well as during the transition between them, are considered. The possibility to purposefully control the properties of such materials is prospective for their practical application.