Description of molecular nanomagnets by the multi-orbital Hubbard model with correlated hopping

Abstract

We present a microscopic description of molecular magnets by the multi-orbital Hubbard model, which includes the correlated hopping term, i.e. the dependence of electron hopping amplitude between orbitals on the degree of their occupancy. In the limit of large Coulomb on-site interaction, we derived the spin Hamiltonian using the perturbation theory. The magnetic coupling constant between two ions we determined in two different ways: a)from the expression obtained in the perturbation calculus and b)from the analysis of distances between the lowest levels of the energy spectrum obtained by the diagonalization of the multi-orbital Hubbard model. The procedure we use can be applied to various nanomagnets, but the final calculations we performed for the molecular ring $C{r}_8$. We showed that the correlated hopping can reduce the antiferromagnetic exchange between ions, what is essential for a proper description of $C{r}_8$.

arXiv comment6 pages, 2 figures, to be published in Physical Review B

References in corpus (14)

• Molecular engineering of antiferromagnetic rings for quantum computation
• First- principle calculations of magnetic interactions in correlated systems
• Magnetic Cluster Excitations
• Quantum computing with antiferromagnetic spin clusters
• Interplay of Mott Transition and Ferromagnetism in the Orbitally Degenerate Hubbard Model
• Effect of local Coulomb interactions on the electronic structure and exchange interactions in Mn12 magnetic molecules
• The Hamiltonian of the V${}_{15}$ Spin System from first-principles Density-Functional Calculations
• Many-body models for molecular nanomagnets
• First-principles modelling of magnetic excitations in Mn12
• Correlated hopping in the Falicov-Kimball model: A large-dimensions study
• Correlated hybridization in transition metal complexes
• Thermodynamic observables of Mn12-acetate calculated for the full spin-Hamiltonian
• Bond-charge Interaction in the extended Hubbard chain
• Two-orbital Hubbard model vs spin $S=1$ Heisenberg model: studies on clusters