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Title: Off-diagonal interactions, Hund's rules, and pair binding in C[sub 60]

Journal Article · · Physical Review, B: Condensed Matter; (United States)
; ; ;  [1]
  1. Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3080 (United States)

We have studied the effect of including nearest-neighbor electron-electron interactions, in particular the off-diagonal (non-density-density) terms, on the spectra of truncated tetrahedral and icosahedral Hubbard molecules, focusing on the relevance of these systems to the physics of doped C[sub 60]. Our perturbation theoretic and exact diagonalization results agree with previous work in that the density-density term suppresses pair binding. However, we find that for the parameter values of interest for C[sub 60], the off-diagonal terms [ital enhance] pair binding, though not enough to offset the suppression due to the density-density term. We also find that the critical interaction strengths for the Hund's rules violating level crossings in C[sub 60][sup [minus]2], C[sub 60][sup [minus]3], and C[sub 60][sup [minus]4] are quite insensitive to the inclusion of these additional interactions.

OSTI ID:
6400960
Journal Information:
Physical Review, B: Condensed Matter; (United States), Vol. 51:9; ISSN 0163-1829
Country of Publication:
United States
Language:
English