Mott transition

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

First-order Mott transition at zero temperature in two dimensions: Variational plaquette study

Abstract: The nature of the metal-insulator Mott transition at zero temperature has been discussed for a number of years. Whether it occurs through a quantum critical point or through a first-order transition is expected to profoundly influence the nature of the finite-temperature phase diagram. In this paper, we study the zero temperature Mott transition in the two-dimensional Hubbard model on the square lattice with the variational cluster approximation. This takes into account the influence of antiferromagnetic short-range correlations. By contrast to single-site dynamical mean-field theory, the transition turns out to be first order even at zero temperature.

Mechanism of Hopping Transport in Disordered Mott Insulators

Abstract: By using a combination of detailed experimental studies and simple theoretical arguments, we identify a novel mechanism characterizing the hopping transport in the Mott insulating phase of Ca2-xSrxRuO4 near the metal-insulator transition. The hopping exponent alpha shows a systematic evolution from a value of alpha=1/2 deeper in the insulator to the conventional Mott value alpha=1/3 closer to the transition. This behavior, which we argue to be a universal feature of disordered Mott systems close to the metal-insulator transition, is shown to reflect the gradual emergence of disorder-induced localized electronic states populating the Mott-Hubbard gap.

Dynamical mean field theory of the antiferromagnetic metal to antiferromagnetic insulator transition

Abstract: The correlation driven metal insulator transition (MIT) or Mott transition is one of the central problems of condensed matter physics. Recently, a great deal of progress has been made in understanding the MIT using the dynamical mean field approach (DMFT), a method which becomes exact in the well-defined limit of infinite lattice coordination [1,2]. However, all studies so far have been confined to the paramagnetic metal (PM) to paramagnetic insulator (PI) transition. In this Letter, we use DMFT to study the transition from the antiferromagnetic metal (AM) to an antiferromagnetic insulator (AI) at zero temperature. The motivation for this work is twofold. Experimentally, the interaction or pressure driven MIT in V2O3 [3,4] and NiS22xSex [4,5] takes place between magnetically ordered states. The Neel temperatures are much smaller than the respective characteristic electronic energy scales. We interpret this as a sign of reduced effective magnetic correlations as compared to estimates obtained from a simple one band Hubbard model. Close to the MIT, the behavior of physical quantities like the specific heat coefficient is, however, different in these two materials. Furthermore, measurements of the magnetic moment seem to indicate that the magnetism in V2O3 is much weaker than in NiS22xSex [6]. This suggests that the strength of the magnetic correlations influences the MIT. We would therefore like to understand how magnetic correlations, which control the scale at which the spin entropy is quenched, affect the MIT and hence, various physical quantities. While we are still far from a realistic modeling of these materials (in this work we consider only commensurate magnetic order and ignore orbital degeneracy and realistic band structure), we present a simple model which, we believe, captures the generic effects of the magnetic correlations on the MIT. We consider a simple one band Hamiltonian,

Transitions between the quantum Hall states and insulators induced by periodic potentials.

Abstract: Transitions between two quantum Hall states or between a quantum Hall state and a Mott insulator induced by periodic potentials are studied in the 1/N expansion. The transitions are found to be continuous in the large-N limit and are described by a critical point that depends on a real parameter \ensuremath{\theta}, which is determined by the topological orders in the quantum Hall states involved in the transition. Some critical exponents and universal quantities are calculated in the large-N limit and shown to be \ensuremath{\theta} dependent.