Analytical diagonalization study of a two-orbital Hubbard model on a two-site molecule

Amendola, Maria Emilia; Romano, Alfonso; Noce, Canio

doi:10.1016/j.physb.2015.10.003

Cited by 5 publications

(2 citation statements)

References 39 publications

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“…At the same time, it has been noticed that the exact solutions to the model can be obtained for small clusters, consisting of several lattice sites [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84]. Intensive investigations of such systems have been carried out both from the point of view of static properties [48-50, 52, 58, 62, 64, 66-68, 71-73, 75-80, 82, 83, 85-88], as well as for dynamical description [54,59,61,70,81,84].…”

Section: Introductionmentioning

confidence: 99%

Hubbard pair cluster in the external fields. Studies of the polarization and susceptibility

Balcerzak

Szałowski

2018

Physica A: Statistical Mechanics and its Applications

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The electric and magnetic polarizations as well as the electric and magnetic susceptibilities of the Hubbard pair-cluster embedded in the external fields were studied by the exact method. Based on the grand canonical ensemble for open system, the numerical calculations were performed for the electron concentration corresponding to the half-filling case. It has been found that the electric and magnetic properties are strictly interrelated, what constitutes a manifestation of a magnetoelectric effect, and the detailed explanation of such behaviour was given. In particular, near the ground state where the transitions are induced by the external fields, discontinuous changes of the studied quantities have been found. They have been associated with the occurrence of the singlet-triplet transitions. An anomalous behaviour of the electric and magnetic polarizations as a function of the temperature, occurring below the critical magnetic field, was illustrated. In the presence of the competing electric and magnetic fields, the influence of Coulombic repulsion on the studied properties was discussed.

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Section: Introductionmentioning

confidence: 99%

Hubbard pair cluster in the external fields. Studies of the polarization and susceptibility

Balcerzak

Szałowski

2018

Physica A: Statistical Mechanics and its Applications

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“…[30,31,32] It should be mentioned that the thermodynamics of such system can be described exactly. The Hubbard dimer has been studied also in the context symmetries [33], density functional theory [34,35], spectral function [36], integrals of motion [37], two-orbital model [38], orbital degeneracy [39] or the extended version of the Hubbard model [40,41] including the electronphonon couplings within Hubbard-Holstein model on a dimer [42]. Other cluster-based Hubbard nanostructures have also been studied [43,44,45], to mention especially those like cube [46,47,48], triangle [49,50] and tetrahedron [49] clusters or a finite chain [51,52,53].…”

Section: Introductionmentioning

confidence: 99%

Magnetocaloric and electrocaloric properties of the Hubbard pair cluster

Szałowski,

Balcerzak

2020

Preprint

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The paper contains the discussion of the magnetocaloric and electrocaloric effect in a model dimer (pair cluster). The system of interest is modelled with a Hubbard Hamiltonian including the external electric and magnetic field. The thermodynamics of such pair is described exactly, on the grounds of the grand canonical ensemble, focusing on the half-filling of energy states. The quantities of interest, such as magnetic entropy, magnetic specific heat as well as isothermal entropy change resulting from the variation of either electric and magnetic field and appropriate Grüeneisen ratios are calculated and discussed in a wide range of external fields. The importance of singlet to triplet transition for the observed behaviour is emphasized. The ranges of direct and inverse caloric effects are found and the manifestations of the magnetoelectric phenomena are described. In particular, the tunability of the magnetocaloric effect with electric field as well as tunability of the electrocaloric effect with magnetic field are demonstrated.

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Magnetocaloric and electrocaloric properties of the Hubbard pair cluster

Szałowski

Balcerzak

2021

Journal of Magnetism and Magnetic Materials

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Analytical diagonalization study of a two-orbital Hubbard model on a two-site molecule

Cited by 5 publications

References 39 publications

Hubbard pair cluster in the external fields. Studies of the polarization and susceptibility

Hubbard pair cluster in the external fields. Studies of the polarization and susceptibility

Magnetocaloric and electrocaloric properties of the Hubbard pair cluster

Magnetocaloric and electrocaloric properties of the Hubbard pair cluster

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