A theory of double exchange is generalized to degenerate states of d electrons in crystal fields. A two-center system with three d electrons is considered. The Coulomb and exchange intercenter interactions and the resonance splitting of exchange multiplets are considered. Group-theoretic classification of the exchange-resonance multiplets in crystal fields is presented. The dependences of the electron hopping parameters on the orbital symmetry and spin of the resonance states involved are clarified. The energy spectrum of a cluster consisting of two nuclei is obtained in the limit when the resonance interactions are weak compared with the intraatomic interactions. It is shown that the Heisenberg exchange parameter is renormalized when electron hopping is included. The results are compared with the conclusions of the P. W. Anderson-H. Hasegawa model.
|Number of pages||5|
|Journal||Soviet Physics, Solid State (English translation of Fizika Tverdogo Tela)|
|State||Published - 1 Jan 1984|
ASJC Scopus subject areas
- Engineering (all)