Valence-skipping and negative-U in the d-band from repulsive local Coulomb interaction
- Strand, Hugo U. R. University of Fribourg, Switzerland and University of Gothenburg, Sweden
-
07.10.2014
Published in:
- Physical Review B. - 2014, vol. 90, no. 15, p. 155108
English
We show that repulsive local Coulomb interaction alone can drive valence-skipping charge disproportionation in the degenerate d-band, resulting in effective negative-U. This effect is shown to originate from anisotropic orbital-multipole scattering, and it occurs only for d1,d4,d6, and d9 fillings (and their immediate surroundings). Explicit boundaries for valence-skipping are derived, and the paramagnetic phase diagram for d4 and d6 is calculated. We also establish that the valence-skipping metal is very different, in terms of its local valence distribution, compared to the atomiclike Hund's metal. These findings explain why transition-metal compounds with the aforementioned d-band fillings are more prone to valence-skipping charge order and anomalous superconductivity.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 233253
- DOI 10.1103/PhysRevB.90.155108
- Persistent URL
- https://folia.unifr.ch/unifr/documents/304140
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