Mott transition

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

Light-Cone Effect and Supersonic Correlations in Bosonic Superfluids

Abstract: We study the spreading of density-density correlations in Bose-Hubbard models after a quench of the interaction strength, using time-dependent variational Monte Carlo simulations. It gives access to unprecedented long propagation times and to dimensions higher than one. In both one and two dimensions, we find ballistic light-cone spreading of correlations and extract accurate values of the light-cone velocity in the superfluid regime. We show that the propagation of correlations is generally supersonic, with a light-cone velocity larger than twice the sound velocity, except at the Mott transition, where the characteristic velocities are equal. Further, we show that in two dimensions the correlation spreading is highly anisotropic and presents nontrivial interference effects.

Mott constant in two-dimensional metal-insulator transition

Abstract: The recent developments of scaling theory of metal–insulator transition in two dimensions are elicited in a good manner. Metal–Insulator transition using exact two-dimensional dielectric function is investigated for a shallow donor in an isolated well of GaAs/Ga1−xAlsAs superlattice system within the effective mass approximation. Vanishing of the donor ionization energy as a function of well width and the donor concentration suggests that the phase transition is not possible even below a well width of 10 A supporting the scaling theory of localization. The effects of Anderson localization, exchange and correlation in the Hubbard model are included in a simple way. The relationship between the present model and the Mott criterion in terms of Hubbard model is also brought out. A simple expression for a Mott constant in 2D, a*Nc1/2 exp (−9.86 exp(−L/a*))=0.123, where Nc is the critical concentration per area, is derived. The critical concentration is enhanced when a random distribution of impurities is considered. The limiting behaviour of well width for a quantum 2D is brought out. The results are compared with the existing data available.

Specific heat of a single-crystalline perovskite,

Abstract: The electronic specific heat coefficients for single crystals of a perovskite-type vanadate system, , are reported. Wilson's ratio has been determined by comparing the data to the Pauli-paramagnetic susceptibility; the value indicates a strong electron correlation in this system. Nevertheless, the effective masses are not so large as expected from the critical-mass-enhancement picture near the Mott transition.

Ultrafast Mott transition driven by nonlinear phonons

Abstract: Nonlinear phononics holds the promise for controlling properties of quantum materials on the ultrashort timescale. Using nonequilibrium dynamical mean-field theory, we solve a model for the description of organic solids, where correlated electrons couple non-linearly to a quantum phonon-mode. Unlike previous works, we exactly diagonalize the local phonon mode within the non-crossing approximation (NCA) to include the full phononic fluctuations. By exciting the local phonon in a broad range of frequencies near resonance with an ultrashort pulse, we show it is possible to induce a Mott insulator-to-metal phase transition. Conventional semiclassical calculations, where the quantum phonon operators are replaced by their classical expectation values, fail to capture the insulator-to-metal transition. This fact, together with the non-thermal character of the photo-induced metal, suggests a leading role of the phononic fluctuations and of the dynamic nature of the state in the vibrationally induced quasiparticle coherence.