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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 paper, the authors investigate how the orbital degeneracy affects the Mott transition at integer fillings different from 3. The calculations are done by fixed-node diffusion Monte Carlo, using a trial function, which permits them to systematically vary the magnetic character of the system.
Abstract: The doped Fullerides can be well described by a Hubbard model, which comprises the partly filled, threefold-degenerate t_1u orbital and the on-site Coulomb interaction U. The orbital degeneracy is known to shift the critical ratio U_c/W for the Mott-Hubbard transition towards larger values. This puts the half-filled alkali-doped Fullerides A_3 C_60 on the metallic side of the transition. Prompted by the recent synthesis of isostructural families of integer-doped Fullerides with different fillings, we investigate how the orbital degeneracy affects the Mott transition at integer fillings different from 3. The calculations are done by fixed-node diffusion Monte Carlo, using a trial function, which permits us to systematically vary the magnetic character of the system.

1 citations

Journal ArticleDOI
TL;DR: In this article, the Mott transition in two-orbital Hubbard systems was investigated using dynamical mean field theory and the self-energy functional approach, and the stability of itinerant quasi-particle states in each band was discussed.
Abstract: We investigate the Mott transitions in two-orbital Hubbard systems. Applying the dynamical mean field theory and the self-energy functional approach, we discuss the stability of itinerant quasi-particle states in each band. It is shown that separate Mott transitions occur at different Coulomb interaction strengths in general. On the other hand, if some special conditions are satisfied for the interactions, spin and orbital fluctuations are equally enhanced at low temperatures, resulting in a single Mott transition. The phase diagrams are obtained at zero and finite temperatures. We also address the effect of the hybridization between two orbitals, which induces the Kondo-like heavy fermion states in the intermediate orbital-selective Mott phase.

1 citations

01 Jan 1991
TL;DR: In this paper, the Mott-Hubbard gap closure induced by high pressure was studied in transition metal compounds and it was shown that the high pressure transition from a magnetic to amore non-magnetic state is not accompanied by crystallographic changes.
Abstract: Many of the Transition Metal (TM) compounds, because of exchange and correlation interactions within the narrow and poorly overlapping d-bands, become antiferromagnetic insulators, the Mott Insulators (MI). The properties of the MI and their gradual transition into the non-correlated metallic state (the Mott Transition) are of crucial important for the elucidation of HTS materials features in particular and to magnetism in general. The transition of the MI into a metal can be achieved either by doping or by high pressure. To yield the definitive data on the Mott transition high pressure work on well characterized materials should be sought. The present studies provide for the first time extensive information on the Mott-Hubbard gap closure induced by high pressure. High pressure studies using Diamond Anvil Cells were conducted in several (TM)I{sub 2} compounds. They all have layered structures and other antiferromagnetically at ambient pressure. {sup 129}I Moessbauer Spectroscopy (MS) was used to study the properties of the (TM){sup 2+} sublattice magnetization as a function of pressure and temperature, and X-ray diffraction was used to look for possible crystallographic transitions and to obtain the equation of state. Results show that the high pressure transition at P{sub c} from a magnetic to amore » non-magnetic state is not accompanied by crystallographic changes. Previous studies{sup 1} with NiI{sub 2} have confirmed the presence of a metallic state at P > P{sub c}. Inherent to the pressure behavior of the magnetic state is the gradual increase of T{sub N} in all cases and a slight increase in the TM{sup 2+} moments with pressure increase. The collapse of the magnetic state is abrupt for some cases (NiI{sub 2}) and gradual for others (CoI{sub 2}), indicative of different band-overlap mechanisms. 2 refs., 5 figs.« less

1 citations

Journal ArticleDOI
TL;DR: The phase diagram of the extended Caron-Pratt model is constructed in this article, and the possible phases, the incompatibility of the order parameters, and the existence of the tricritical point are determined.
Abstract: The phase diagram of the extended Caron-Pratt model is constructed. Competing order parameters describe ferromagnetic and metal–insulator phase transitions. The possible phases, the incompatibility of the order parameters, and the existence of the tricritical point are determined. Das Phasendiagramm des erweiterten Caron-Pratt-Modells wird konstruiert. Konkurrierende Ordnungsparameter beschreiben ferromagnetische und Metall–Isolator-Ubergange. Die moglichen Phasen, die Inkompatibilitat der Ordnungsparameter und die Existenz des trikritischen Punktes werden bestimmt.

1 citations

Journal ArticleDOI
TL;DR: In this paper, the metal-insulator transition in a generalized Hubbard model with bondcharge interaction has been studied by means of the auxiliary field technique, and the phase diagram in the parameter space spanned by the effective kinetic energy and the effective bond-charge interaction is presented for the three-dimensional case.
Abstract: The metal-insulator transition in a generalized Hubbard model with bondcharge interaction has been studied by means of the auxiliary field technique. The system exhibits both the conventional Mott-Hubbard transition, characterized by a continuous change in the number of current carriers, and a novel first-order metal-insulator transition owing to the bond-charge interaction, at which there is a discontinuity in the number of current carriers. The phase diagram in the parameter space spanned by the effective kinetic energy and the effective bond-charge interaction is presented for the three-dimensional case.

1 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202334
202271
202165
202064
201968
201871