Mott transition

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

High frequency thermoelectric response in correlated electronic systems

Abstract: We derive a general formalism for evaluating the high-frequency limit of the thermoelectric power of strongly correlated materials, which can be straightforwardly implemented in available rst principles LDA+DMFT programs. We explore this formalism using model Hamiltonians and we investigate the validity of approximating the static thermoelectric power S0, by its hightemperature limit, S . We point out that the behaviors of S and S0 are qualitatively dierent for a correlated Fermi liquid near the Mott transition, when the temperature is in the coherent regime. When the temperature is well above the coherent regime, e.g., when the transport is dominated by incoherent excitations, S provides a good estimation of S0.

Variational local moment approach: From Kondo effect to Mott transition in correlated electron systems

Abstract: The variational local moment approach (VLMA) solution of the single impurity Anderson model is presented. It generalizes the local moment approach of Logan et al. by invoking the variational principle to determine the lengths of local moments and orbital occupancies. We show that VLMA is a comprehensive, conserving and thermodynamically consistent approximation and treats both Fermi and non-Fermi liquid regimes as well as local moment phases on equal footing. We tested VLMA on selected problems. We solved the single- and multi-orbital impurity Anderson model in various regions of parameters, where different types of Kondo effects occur. The application of VLMA as an impurity solver of the dynamical mean-field theory, used to solve the multi-orbital Hubbard model, is also addressed.

Finite-Temperature Mott Transition in Two-Dimensional Frustrated Hubbard Models

Abstract: We investigate the Hubbard model on two typical frustrated lattices in two dimensions, the kagome lattice and the anisotropic triangular lattice, by means of the cellular dynamical mean field theory. We show that the metallic phase is stabilized up to fairly large Hubbard interactions under strong geometrical frustration in both cases, which results in heavy fermion behavior and several anomalous properties around the Mott transition point. In particular, for the anisotropic triangular lattice, we find novel reentrant behavior in the Mott transition in the moderately frustrated parameter regime, which is caused by the competition between Fermi-liquid formation and magnetic correlations. It is demonstrated that the reentrant behavior is a generic feature inherent in the Mott transition with intermediate geometrical frustration, and indeed in accordance with recent experimental findings for organic materials.

Collective excitations and the nature of Mott transition in undoped gapped graphene

Abstract: The particle?hole continuum (PHC) for massive Dirac fermions provides an unprecedented opportunity for the formation of two collective split-off states, one in the singlet and the other in the triplet (spin-1) channel, when the short-range interactions are added to the undoped system. Both states are close in energy and are separated from the continuum of free particle?hole excitations by an energy scale of the order of the gap parameter ?. They both disperse linearly with two different velocities, reminiscent of spin?charge separation in Luttinger liquids. When the strength of Hubbard interactions is stronger than a critical value, the velocity of singlet excitation, which we interpret as a charge composite boson, becomes zero and renders the system a Mott insulator. Beyond this critical point the low-energy sector is left with a linearly dispersing triplet mode?a characteristic of a Mott insulator. The velocity of the triplet mode at the Mott criticality is twice the velocity of the underlying Dirac fermions. The phase transition line in the space of U and ? is in qualitative agreement with our previous dynamical mean field theory calculations.

D charge-density-wave versus superconducting phase fluctuations in underdoped high-Tc superconductors

Abstract: The underdoped region in high-T c superconductors is characterized by an increase of the d-wave gap and a decrease of the superconducting transition temperature T c with decreasing doping. Two effects may cause such a behavior in the t - J model. On the one hand, superconductivity competes and may also coexist with a d charge-density-wave state. We discuss this effect by studying the phase diagram of the t - J model at large N (N is the number of internal degrees of freedom), the gap structure in the coexisting region and the resulting c-axis tunneling spectra. On the other hand, we give rather general arguments in favor of a strong reduction of the phase stiffness near a Mott transition and calculate the resulting drop in T c at low dopings due to thermal phase fluctuations.