1973/05/01 by Isamu Okada, Kei Yosida · 2 citations
Engineering · Physics and Astronomy · #Advanced Chemical Physics Studies #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena
paper · doi:10.1143/ptp.49.1483
crossref issued 1973/05/01 · crossref published 1973/05/01 · crossref published-print 1973/05/01 · openalex publication_date 1973/05/01 · crossref created 2005/12/16 · crossref deposited 2017/08/24 · openalex created_date 2025/10/10 · crossref indexed 2026/07/31 · openalex updated_date 2026/07/31
The theory of the singlet ground state for the s-d exchange model is extended to the core of d-electrons with orbital degeneracy. The effective s-d Hamiltonian is derived from the extended Anderson Hamiltonian by the Schrieffer-Wolff canonical transformation. On the basis of the effective Hamiltonian, the ground-state wave function and the ground-state energy are calculated. The anomalous part of the ground-state energy is given by -Dexp[N/(2l+1)ρJ], independently of the d-electron number, when the Hund coupling is neglected compared with the effective s-d interaction. This binding energy is much larger than that for a localized s-electron because of an extra factor of 1/(2l+1) in the exponent. This large value is caused mainly by the orbital quenching. For a more realistic case in which the Hund coupling is larger than the s-d interaction, it reduces to a smaller value of -Dexp[(2l+1)N/ρJ] for a half-filled shell in which orbital exchange does not exist. This value is due purely to the spin quenching. Qualitative discussion is given about the spin quenching and orbital quenching on the effective Hamiltonian derived for n=2l, n being the number of d-electrons.