Магнитные топологические сплавы на основе дираковского полуметалла Cd3As2: легирование атомами Cr, Mn и Fe

Письма в Журнал экспериментальной и теоретической физики. 2025. Т. 121. № 9. С. 771–781.

Кулатов Э. Т., Успенский Ю. А., Kugel K.

According to theoretical models, the introduction of magnetic atoms into a Dirac semimetal splits the Dirac cone into two Weyl cones, thus forming a magnetic Weyl semimetal attractive for applications. In the present work, this process is investigated ab initio, using the example of doping the Dirac half-metal Cd3As2 with Cr, Mn and Fe atoms. For the cases of ferromagnetic and antiferromagnetic spin ordering in (Cd1-xMx)3As2, (M=Cr, Mn, Fe) alloys, the band structure, Fermi surface, electron velocity at the Fermi level and Drude plasma frequency are calculated, and the relaxation time at temperature T→0 K are estimated. It follows from the calculations that in ferromagnetic alloys one Weyl cone, as a rule, is destroyed due to hybridization of electronic states of Cd3As2 with 3d-orbitals of atoms M. The condition of the conservation of the second Weyl cone is its falling into an energy window free of 3d-states of M atoms. The existence of such windows is closely related to the energy and filling of 3d↑- and 3d↓-bands of M atoms, the type of spin ordering (ferro- or antiferromagnetic) and the chemical composition of the alloy. In particular, such windows are absent in antiferromagnetic alloys, except in the case of M=Mn. The estimates show that the Weyl cone, if conserved, dominates the transport properties of (Cd1-xMx)3As2, which is in agreement with the experimental results. 

Keywords: Band structure, зонная структура, Dirac cone, конус Дирака, topological alloys, топологические сплавы