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Mott transition
About: Mott transition is a research topic. Over the lifetime, 2444 publications have been published within this topic receiving 78401 citations.
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TL;DR: In this article, an exact generalized Bogoliubov transformation for the spin 3/2 Hubbard model with large anti-Hunds rule coupling near half filling is developed, and a non-Fermi liquid order parameter, usually associated with extended s-wave superconductivity, will appear selfconsistently as soon as a finite density $ n $ holes are introduced.
Abstract: We develop an exact generalized Bogoliubov transformation for the spin 3/2 Hubbard model with large anti-Hunds rule coupling near half filling. Since our transformation is unitary, we can thereafter employ standard approximate mean field theory methods in the full Hilbert space to analyze the doped Mott insulator, in contrast to a conventional approach based on truncated Hilbert spaces complemented with hard core constraints. The ground state at exactly half filling is an insulating (Mott) singlet, and according to our analysis a non-Fermi liquid order parameter $ \Delta $ usually associated with extended s-wave superconductivity, will appear self-consistently as soon as a finite density $ n $ holes are introduced. The non-Fermi liquid behavior is a consequence of the nonlinear nature of the unitary transformation mapping the Mott singlet state to a Fock vacuum which introduces anomalous terms such as $\Delta n$ in the effective Lagrangian. Our analysis uses an approach that generalizes readily to multi-band Hubbard models and could provide a mechanism whereby a non-Fermi liquid order parameter proportional to density is developed in Mott insulators with locally entangled ground states. For more complicated systems, such an order parameter could coexist naturally with a variety of other order parameters.
1 citations
Journal Article•
TL;DR: In this article, the authors obtained an asymmetric Hamiltonian for the half-filled strongly correlated system by ignoring the jumping of electrons with spin-σ between lattice sites when the motion of electron with spin σ is considered, and applied the mean field approximation to get the quasi-particle spectrum of the Hamiltonian.
Abstract: Starting from the standard Hubbard model, this paper obtained an asymmetric Hamiltonian for the half-filled strongly correlated system by ignoring the jumping of electrons with spin-σ between lattice sites when the motion of electrons with spin σ is considered. The mean field approximation is applied to get the quasi-particle spectrum of the Hamiltonian. The results at zero-temperature and finite temperature are analyzed,the possibility and critical temperature of Mott metal-insulator transition is also investigated.
1 citations
TL;DR: In this article, the authors studied the Mott type superconductor-insulator transition with disorder effect in metallic thin film and analyzed the critical behavior of superconductivity by using the Matsubara-Matsuda model and the double-time Green's function.
Abstract: We study the mechanism of Mott type superconductor–insulator (S–I) transition with disorder effect in metallic thin film. The critical behavior of superconductivity is examined analytically by using the Matsubara–Matsuda model and the double-time Green’s function. The critical value of disorder, sheet resistance corresponding to the transition point and the critical exponents ν and z are obtained.
1 citations
TL;DR: In this paper, the authors studied the excitation energy for slow changes of the hopping parameter in the Falicov-Kimball model with nonequilibrium dynamical mean-field theory, and showed that the exponent depends explicitly on the spectrum of the system in the initial state and on the smoothness of the ramp protocol.
Abstract: We study the excitation energy for slow changes of the hopping parameter in the Falicov-Kimball model with nonequilibrium dynamical mean-field theory. The excitation energy vanishes algebraically for long ramp times with an exponent that depends on whether the ramp takes place within the metallic phase, within the insulating phase, or across the Mott transition line. For ramps within metallic or insulating phase the exponents are in agreement with a perturbative analysis for small ramps. The perturbative expression quite generally shows that the exponent depends explicitly on the spectrum of the system in the initial state and on the smoothness of the ramp protocol. This explains the qualitatively different behavior of gapless (e.g., metallic) and gapped (e.g., Mott insulating) systems. For gapped systems the asymptotic behavior of the excitation energy depends only on the ramp protocol and its decay becomes faster for smoother ramps. For gapless systems and sufficiently smooth ramps the asymptotics are ramp-independent and depend only on the intrinsic spectrum of the system. However, the intrinsic behavior is unobservable if the ramp is not smooth enough. This is relevant for ramps to small interaction in the fermionic Hubbard model, where the intrinsic cubic fall-off of the excitation energy cannot be observed for a linear ramp due to its kinks at the beginning and the end.
1 citations