Band splitting in altermagnet CrSb

Altermegnets are a class of metallic magnets characterized by spin-split electron bands. Like antiferromagnets they lack spontaneous bulk magnetisation. The standard description of the momentum dependent spin splitting of electron bands in altermagnets is based on the spin groups approach, which is valid when relativistic interactions are neglected. The problem of electron bands spin splitting in hexagonal altermagnet CrSb is discussed using magnetic groups formalism that allows to establish the additional spin splitting missed in frame of exchange approximation.