Mott transition

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

Electron-phonon interaction in strongly correlated electron systems: relevance of antiferromagnetic correlations.

Abstract: The interplay between electron-phonon interaction and strong electronic correlation is analyzed by means of Dynamical Mean Field Theory. Suppressing all antiferromagnetic correlations, the electron-phonon interaction is found to be strongly suppressed by Coulomb repulsion. In particular, close to the Mott transition at half-filling the electron-phonon interaction has very little effect on quasiparticles: In fact it is possible to describe the low-energy physics in terms of an effective Hubbard model with a slightly renormalized repulsive coupling. The situation changes completely if antiferromagnetic correlations are included: Electron-phonon interaction has a strong effect on the electronic self-energy even for large values of the Coulomb repulsion. Phonon-induced modifications of electronic properties like, e.g. photoemission spectra, are therefore expected to be more pronounced in underdoped cuprates where antiferromagnetic correlations are stronger than in overdoped.

Effect of interaction and temperature on quantum phase transition in anisotropic square-octagon lattice*

Abstract: We investigate the effect of interaction, temperature, and anisotropic parameter on the quantum phase transitions in an anisotropic square-octagon lattice with fermions under the framework of the single band Hubbard model through using the combination of cellular dynamical mean field theory and a continuous time Monte Carlo algorithm. The competition between interaction and temperature shows that with the increase of the anisotropic parameter, the critical on-site repulsive interaction for the metal–insulator transition increases for fixed temperature. The interaction–anisotropic parameter phase diagram reveals that with the decrease of temperature, the critical anisotropic parameter for the Mott transition will increase for fixed interaction cases.

High-pressure Mössbauer spectroscopy, a unique tool for unraveling the nature of electron correlations in Mott insulators

Abstract: Combining the methods of Mossbauer spectroscopy, synchrotron XRD, and resistivity and using diamond-anvil cells enables the discovery and studies of new phenomena in magnetism and electronic correlation at high density. It is shown that Hund's rule concerning the high-spin state in TM-compounds does not hold in this regime resulting in spin-crossover and collapse of the magnetic state for even-valence TM ions and for the decline of magnetic exchange in the odd-valence species. This mechanism competes with the breakdown of the d–d electron correlation (Mott transition) in transforming the Mott insulators into normal metals. The experimental issues are described and examples of magnetic studies at very high-pressures are portrayed.

Phase control in multiply looped rings

Abstract: A material-designing principle in which a hierarchical structure is achieved by a series of steps of folding a low-order structure into a high-order structure is introduced in comparison with periodic arrays of unit cells. Multiply looped rings are a typical example, in which a ring consists of L components, which are themselves rings consisting of L components, and so on. A lattice of multiply looped rings when the number of hierarchies is greater than two is three dimensional, as suggested by the existence of an Anderson transition, in which a quantum particle runs through a random potential. The Curie temperature of ferromagnetic transition and the critical strength of electron–electron interaction in a Mott transition are demonstrated to be well modulated by changing L in the hierarchical structure, suggesting that material design can be achieved using the hierarchical structure to yield physical properties as desired.

Electrical inhomogeneity at the Mott transition in the band width controlled κ-(BEDT-TTF) 2Cu[N(CN) 2Br

Abstract: The electronic phase separation on macroscopic scale is studied in the organic Mott system κ-(BEDT-TTF)2Cu[N(CN)2]Br by means of scanning micro-region infrared spectroscopy using the synchrotron radiation. The phase separation appears in the vicinity of the Mott boundary in the single crystals of which the band width is controlled by partly substituting the BEDT-TTF molecule with the deuterated one. The transport properties under the phase separation are considered to be influenced by the percolation process of the domains.