Mott transition

About: Mott transition is a research topic. Over the lifetime, 2444 publications have been published within this topic receiving 78401 citations.

Mott-Anderson Transition in Molecular Conductors: Influence of Randomness on Strongly Correlated Electrons in the κ-(BEDT-TTF)2X System

Abstract: The Mott-Anderson transition has been known as a metal-insulator (MI) transition due to both strong electron-electron interaction and randomness of the electrons. For example, the MI transition in doped semiconductors and transition metal oxides has been investigated up to now as a typical example of the Mott-Anderson transition for changing electron correlations by carrier number control in concurrence with inevitable randomness. On the other hand, molecular conductors have been known as typical strongly correlated electron systems with bandwidth controlled Mott transition. In this paper, we demonstrate our recent studies on the randomness effect of the strongly correlated electrons of the BEDT-TTF molecule based organic conductors. X-ray irradiation on the crystals introduces molecular defects in the insulating anion layer, which cause random potential modulation of the correlated electrons in the conductive BEDT-TTF layer. In combination with hydrostatic pressure, we are able to control the parameters for randomness and correlations for electrons approaching the Mott-Anderson transition.

Exact Solution of the Infinite-Range-Hopping Bose–Hubbard Model

Abstract: The thermodynamic behavior of the Bose–Hubbard model is solved for any temperature and any chemical potential. It is found that there is a range of critical coupling strengths λ c1 < λ c2 < λ c3 < ⋅⋅⋅ in this model. For coupling strengths between λ c,k and λ c,k+1, Bose–Einstein condensation is suppressed at densities near the integer values ρ = 1,...,k with an energy gap. This is known as a Mott insulator phase and was previously shown only for zero temperature. In the context of ultra-cold atoms, this phenomenon was experimentally observed in 2002(1) but, in the Bose–Hubbard model, it manifests itself also in the pressure-volume diagram at high pressures. It is suggested that this phenomenon persists for finite-range hopping and might also be experimentally observable.

Self-energy and vertex functions from hybridization-expansion continuous-time quantum Monte Carlo for impurity models with retarded interaction

Abstract: Optimized measurements for the susceptibility, self-energy, as well as three-leg and four-leg vertex functions are introduced for the continuous-time hybridization-expansion quantum Monte Carlo solver for the impurity model in the presence of a retarded interaction. The self-energy and vertex functions are computed from impurity averages which involve time integrals over the retarded interaction. They can be evaluated efficiently within the segment representation. These quantities are computed within dynamical mean-field theory in the presence of plasmonic screening. In the antiadiabatic regime, the self-energy is strongly renormalized but retains features of the low energy scale set by the screened interaction. An explicit expression for its high-frequency behavior is provided. Across the screening driven and interaction driven metal-insulator transitions, the vertex functions are found to exhibit similar structural changes, which are hence identified as generic features of the Mott transition.

Influence of Bi3+ doping on electronic transport properties of La0.5−xBixCa0.5MnO3 manganites

Abstract: Electronic transport properties of La0.5−xBixCa0.5MnO3 (x=0, 1/16, 1/8, 1/4, 3/8 and 1/2) compounds have been studied systematically to investigate their charge ordering (CO) behaviors. The results show that the CO temperature increases with the substitution of Bi3+ ion for La3+ ion, suggesting that the charge ordering is enhanced. This is attributed to the special role of the 6s2 lone pair of Bi3+. It is found that for all the samples the adiabatic small polaronic conduction mechanism is responsible for the transport behavior above CO transition, whereas Mott's variable range hopping mechanism dominates below the CO transition. In addition, the electronic transport behavior of La0.5−xBixCa0.5MnO3 compounds is high sensitive to an external magnetic field, which could raise fresh opportunities for application in magnetic sensors.

Effect of discrete quark momenta on the Goldstone mode in a magnetic field

Abstract: The meson static properties are investigated in a Pauli-Villars regularized Nambu--Jona-Lasinio model in a strong magnetic field. The quark dimension reduction leads to a sudden jump of the mass of the Goldstone mode at the Mott transition temperature. A consequence of such a jump may be some interesting phenomena in relativistic heavy ion collisions, where the strong magnetic field can be created. For instance, when the formed fireball cools down, there might be a sudden enhancement of neutral pions at the Mott transition temperature.