Correlated hopping of electrons: Effect on the Brinkman-Rice transition and the stability of metallic ferromagnetism
نویسندگان
چکیده
We study the Hubbard model with bond-charge interaction ~‘‘correlated hopping’’! in terms of the Gutzwiller wave function. We show how to express the Gutzwiller expectation value of the bond-charge interaction in terms of the correlated momentum-space occupation. This relation is valid in all spatial dimensions. We find that in infinite dimensions, where the Gutzwiller approximation becomes exact, the bond-charge interaction lowers the critical Hubbard interaction for the Brinkman-Rice metal-insulator transition. The bondcharge interaction also favors ferromagnetic transitions, especially if the density of states is not symmetric and has a large spectral weight below the Fermi energy.
منابع مشابه
On metallic ferromagnetism of a generalized Hubbard model with correlated hopping
In the paper a possibility of metallic ferromagnetic state realization in a generalized Hubbard model with more complete accounting of electron-electron interactions, in particular, the correlated hopping and exchange interaction integrals is investigated. Recently obtained by means of mean-field approximation single electron energy spectrum is used for the description of finite temperature pro...
متن کاملErratum: Large Fermi Surface of Heavy Electrons at the Border of Mott Insulating State in NiS2
One early triumph of quantum physics is the explanation why some materials are metallic whereas others are insulating. While a treatment based on single electron states is correct for most materials this approach can fail spectacularly, when the electrostatic repulsion between electrons causes strong correlations. Not only can these favor new and subtle forms of matter, such as magnetism or sup...
متن کاملTemperature-induced metal-insulator transition in a narrow-band model with non-equivalent Hubbard subbands at half-filling
In the present paper the temperature-induced metal-insulator transition is studied in a generalized Hubbard model with correlated hopping using recently obtained expression for energy gap. The dependence of energy gap on concentration of doubly occupancy leads to increasing energy gap width with increase of temperature. Thus narrow-band system can undergo transition from a metallic state to an ...
متن کاملDynamical mean-field theory study of Nagaoka ferromagnetism
We revisit Nagaoka ferromagnetism in the U= Hubbard model within the dynamical mean-field theory DMFT using the recently developed continuous time quantum Monte Carlo method as the impurity solver. The stability of Nagaoka ferromagnetism is studied as a function of the temperature, the doping level, and the next-nearest-neighbor lattice hopping t . We found that the nature of the phase transiti...
متن کاملExperimental evaluation of thermal stability of PS- MWCNT nanocomposite as a real-time dosimeter
Introduction: Carbon nanotubes (CNTs) are ideal reinforcing fillers for a polymer matrix, because of their nanometer size, high aspect ratio and, more importantly, their excellent mechanical strength, and electrical and thermal conductivity. The CNTs are categorized into two groups: SWCNT and MWCNT. MWCNTs would have diameters ranging from 2 to 100 nm and lengths of up to tens ...
متن کامل