scholarly journals Ferromagnetism in multiband Hubbard models: From weak to strong Coulomb repulsion

1996 ◽  
Vol 54 (6) ◽  
pp. 4056-4067 ◽  
Author(s):  
Karlo Penc ◽  
Hiroyuki Shiba ◽  
Frédéric Mila ◽  
Takuya Tsukagoshi
Keyword(s):  
Coulomb Repulsion ◽  
Hubbard Models ◽  
Strong Coulomb

scholarly journals Superlight pairs in face-centred-cubic extended Hubbard models with strong Coulomb repulsion

2022 ◽  
Author(s):  
Ganiyu Debo Adebanjo ◽  
Pavel Kornilovitch ◽  
James Peter Hague
Keyword(s):  
Transition Temperature ◽  
Three Dimensional ◽  
Coulomb Repulsion ◽  
Hubbard Models ◽  
Cubic Lattices ◽  
Wide Range ◽  
Strong Coulomb ◽  
Energy Ratios ◽  
High Transition ◽  
Fcc Structure

Abstract The majority of fulleride superconductors with unusually high transition-temperature to kinetic-energy ratios have a face-centred-cubic (FCC) structure. We demonstrate that, within extended Hubbard models with strong Coulomb repulsion, paired fermions in FCC lattices have qualitatively different properties than pairs in other three-dimensional cubic lattices. Our results show that strongly bound, light, and small pairs can be generated in FCC lattices across a wide range of the parameter space. We estimate that such pairs can Bose condense at high temperatures even if thelattice constant is large (as in the fullerides).

Bond-charge coulomb repulsion in peierls-hubbard models

1988 ◽  
Vol 38 (16) ◽  
pp. 12043-12046 ◽  
Author(s):  
D. K. Campbell ◽  
J. Tinka Gammel ◽  
E. Y. Loh
Keyword(s):  
Coulomb Repulsion ◽  
Hubbard Models ◽  
Bond Charge

scholarly journals Fractional orbital occupation of spin and charge in artificial atoms

2011 ◽  
Vol 89 (2) ◽  
pp. 213-217 ◽  
Author(s):  
Catherine J. Stevenson ◽  
Jordan Kyriakidis
Keyword(s):  
Coulomb Repulsion ◽  
Spin Projection ◽  
Spin Correlations ◽  
The Core ◽  
Valence Electrons ◽  
Charge Correlations ◽  
Inert Core ◽  
Strong Coulomb ◽  
The Common ◽  
Orbital Occupation

We present results on spin and charge correlations in two-dimensional quantum dots as a function of increasing Coulomb strength (dielectric constant). We look specifically at the orbital occupation of both spin and charge. We find that charge and spin evolve separately, especially at low Coulomb strength. For the charge, we find that a hole develops in the core orbitals at strong Coulomb repulsion, invalidating the common segregation of confined electrons into an inert core and active valence electrons. For excitations, we find a total spin-projection Sz = –1/2 breaks apart into separate occupations of net positive and negative spin. This dissociation is caused by spin correlations alone. Quantum fluctuations arising from long-range Coulomb repulsion destroy the spin dissociation and eventually results in all orbitals carrying a negative spin.

scholarly journals Эффективные взаимодействия, индуцированные спин-орбитальной связью в сверхпроводящих нанопроволоках в режиме сильных корреляций

2020 ◽  
Vol 62 (9) ◽  
pp. 1447
Author(s):  
А.О. Злотников ◽  
С.В. Аксенов ◽  
М.С. Шустин
Keyword(s):  
Coupling Parameter ◽  
Coulomb Repulsion ◽  
Open Boundary ◽  
Spin Orbit Coupling ◽  
Edge States ◽  
Open Boundary Conditions ◽  
Strong Electron ◽  
Effective Interactions ◽  
Strong Coulomb ◽  
Superconducting Nanowire

Abstract In the second order of the operator form of the perturbation theory, the effective interactions in a superconducting nanowire have been obtained at the strong electron correlations, when the spin–orbit coupling parameter is comparable with the hopping integral. Using the exact diagonalization technique, in short nanowires with the open boundary conditions at the strong Coulomb repulsion, the excitations corresponding to the Majorana edge states with the energy below the value of a bulk superconducting gap have been demonstrated.

scholarly journals Ferromagnetism in d-Dimensional SU(n) Hubbard Models with Nearly Flat Bands

2021 ◽  
Vol 182 (1) ◽  
Author(s):  
Kensuke Tamura ◽  
Hosho Katsura
Keyword(s):  
Single Particle ◽  
Ground States ◽  
Coulomb Repulsion ◽  
Particle Spectrum ◽  
Finite Range ◽  
Rigorous Results ◽  
Hubbard Models ◽  
Flat Bands ◽  
Unit Cells ◽  
Number Of Particles

AbstractWe present rigorous results for the SU(n) Fermi–Hubbard models with finite-range hopping in d ($$\ge 2$$ ≥ 2 ) dimensions. The models are defined on a class of decorated lattices. We first study the models with flat bands at the bottom of the single-particle spectrum and prove that the ground states exhibit SU(n) ferromagnetism when the number of particles is equal to the number of unit cells. We then perturb the models by adding particular hopping terms and make the bottom bands dispersive. Under the same filling condition, it is proved that the ground states remain SU(n) ferromagnetic when the bottom bands are sufficiently flat and the Coulomb repulsion is sufficiently large.

scholarly journals Superlight Small Bipolarons in the Presence of a Strong Coulomb Repulsion

2007 ◽  
Vol 98 (3) ◽  
Author(s):  
J. P. Hague ◽  
P. E. Kornilovitch ◽  
J. H. Samson ◽  
A. S. Alexandrov
Keyword(s):  
Coulomb Repulsion ◽  
Strong Coulomb
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