Mott transition

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

Mott transition and superconductivity

Abstract: Superconducting state where Luttinger theorem is violated is incompatible with the one-electron metallic spectrum, and therefore Coulomb correlations which diminish the density of states on the Fermi level form the conditions which are favourable for superconductivity providing the crystal is stable with respect to the lattice rearrangement, the antiferromagnetic transition etc.

Alpha-Particle Condensation in Nuclear Systems

Abstract: The onset of quartetting, i.e. α-particle condensation, in symmetric and asymmetric nuclear matter is studied with the help of an in-medium modified four nucleon equation. It is found that at very low density quartetting wins over pairing, because of the strong binding of the α-particles. The critical temperature can reach values up to around 8 MeV. The disappearance of α-particles with increasing density, i.e. the Mott transition, is investigated. In finite nuclei the Hoyle state, that is the 02+ of 12C is identified as an 'α-particle condensate' state. It is conjectured that such states also exist in heavier nα-nuclei, like 16O, 20Ne, etc. The sixth 0+ state in 16O is proposed as an analogue to the Hoyle state. The Gross-Pitaevski equation is employed to make an estimate of the maximum number of α particles a condensate state can contain. Possible quartet condensation in other systems is discussed briefly.

Characteristics of the Charged Hole in the One-Dimensional Mott Insulator

Abstract: Charge excitations in the one-dimensional Hubbard model are investigated, with the use of the Bethe-Ansatz method, by inserting the charged hole into the Mott insulator. The density of states and the momentum-dependent susceptibility for the charged hole are shown to have a large enhancement due to the formation of the Hubbard gap. The logarithmic anomaly near 4k F for the latter quantity is investigated in the vicinity of the Mott insulator. The compressibility and the specific heat calculated in the whole temperature region are discussed in connection with the characteristics of the charged holes.

Investigations on Si‐doped AlGaN: Below and above the Mott density

Abstract: Si doped AlxGa1-xN layers with x ranging from 0 to 45% have been grown by metal-organic vapour phase epitaxy in order to study their electrical properties. The Si doping concentration was varied over a wide range below and above the theoretically expected Mott density. By per­forming variable temperature Hall-effect measurements on such epilayers, we could evaluate the donor ionization energy as a function of the Al content x and the Si doping concentration. As expected, we observed a very low ionization energy for Si concentrations above the Mott density (for which the conductivity changes towards metallic conductivity). The evaluated ionization energies for low carrier concentrations fit well with the predicted Si ionization energies (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Critical behavior of dynamic vortex Mott transition in superconducting arrays at fractional vortex densities

Abstract: We study the differential resistivity transition of two-dimensional superconducting arrays induced by an external driving current, in the presence of thermal fluctuations and a magnetic field corresponding to $f$ flux quantum per plaquette. Recent experiments have identified this transition as a dynamic vortex Mott insulator transition at vortex densities near rational values of $f$. The critical behavior is determined from a scaling analysis of the current-voltage relation near the transition, obtained by Monte Carlo simulations of a Josephson-junction array model in the vortex representation. For a square-lattice array, the critical exponents obtained near $f=1/2$ are consistent with the experimental observations. The same scaling behavior is observed near $f=1/3$. For a honeycomb array, although similar results are obtained for $f=1/3$, the transition is absent for $f=1/2$, consistent with an incommensurate vortex phase.