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Mott transition
About: Mott transition is a research topic. Over the lifetime, 2444 publications have been published within this topic receiving 78401 citations.
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TL;DR: In this article, a simple yet quantitative statistical mechanical calculation in a model that incorporates cooperative lattice distortions coupled to the electronic degrees of freedom was performed to reproduce the observed dependence of the transition temperature on cation radius in the well-studied manganite and nickelate materials.
Abstract: Metal to insulator transitions (MITs) driven by strong electronic correlations are common in condensed matter systems, and are associated with some of the most remarkable collective phenomena in solids, including superconductivity and magnetism. Tuning and control of the transition holds the promise of novel, low power, ultrafast electronics, but the relative roles of doping, chemistry, elastic strain and other applied fields has made systematic understanding difficult to obtain. Here we point out that existing data on tuning of the MIT in perovskite transition metal oxides through ionic size effects provides evidence of systematic and large effects on the phase transition due to dynamical fluctuations of the elastic strain, which have been usually neglected. This is illustrated by a simple yet quantitative statistical mechanical calculation in a model that incorporates cooperative lattice distortions coupled to the electronic degrees of freedom. We reproduce the observed dependence of the transition temperature on cation radius in the well-studied manganite and nickelate materials. Since the elastic couplings are generically quite strong, these conclusions will broadly generalize to all MITs that couple to a change in lattice symmetry.
2 citations
TL;DR: In this article, the projected SO(5) (pSO(5)) Hamiltonian was used to explain the magnon mass gap in underdoped cuprate superconductor-normal-superconductor junction.
Abstract: The projected SO(5) (pSO(5)) Hamiltonian incorporates the quantum spin and superconducting fluctuations of underdoped cuprates in terms of four bosons moving on a coarse grained lattice. A simple mean field approximation can explain some key feautures of the experimental phase diagram: (i) The Mott transition between antiferromagnet and superconductor, (ii) The increase of T_c and superfluid stiffness with hole concentration x and (iii) The increase of antiferromagnetic resonance energy as sqrt{x-x_c} in the superconducting phase. We apply this theory to explain the ``two gaps'' problem found in underdoped cuprate Superconductor-Normal- Superconductor junctions. In particular we explain the sharp subgap Andreev peaks of the differential resistance, as signatures of the antiferromagnetic resonance (the magnon mass gap). A critical test of this theory is proposed. The tunneling charge, as measured by shot noise, should change by increments of Delta Q= 2e at the Andreev peaks, rather than by Delta Q=e as in conventional superconductors.
2 citations
TL;DR: In this article, a generalized Bose-Hubbard model on a checkerboard lattice with topologically nontrivial flat-band was studied and the mean-field method was used to decouple the model Hamiltonian and obtained phase diagram by Landau theory of second-order phase transition.
Abstract: In this paper, we studied a generalized Bose-Hubbard model on a checkerboard lattice with topologically nontrivial flat-band. We used mean-field method to decouple the model Hamiltonian and obtained phase diagram by Landau theory of second-order phase transition. We further calculate the energy gap and the dispersion of quasi-particle or quasi-hole in Mott insulator state and found that in strong interaction limit the quasi-particles or the quasi-holes also have flat bands.
2 citations
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TL;DR: In this paper, it was shown that the Mott criterion is applicable not only to heavily doped semiconductors, but also to many other materials and systems, including strongly correlated transition-metal and rare-earth-metal compounds, such as vanadium oxides.
Abstract: September 30, 2015 marks the 110th anniversary of the birth of the famous English physicist N. F. Mott. This article is dedicated to his memory. Here we consider the problem of metal-insulator transition. It is shown that the Mott criterion $a_{B}(n_{c})^{1/3} \approx 0.25$ is applicable not only to heavily doped semiconductors, but also to many other materials and systems, including strongly correlated transition-metal and rare-earth-metal compounds, such as vanadium oxides. A special emphasis is placed to the 'paramagnetic metal - antiferromagnetic insulator' transition in $V_{2}O_{3}$ doped with chromium. In Supplement we also briefly consider the history and state of the art of the Mott transition problem.
2 citations
TL;DR: In this paper, a model of spinless fermions on the square latticeZ2 with an interaction potential of strengthU>0 at distance one and strengthJ at distance two, in the largeU limit |t|, |J|≪U, wheret is the hopping amplitude.
Abstract: We consider a model of spinless fermions on the square latticeZ2 with an interaction potential of strengthU>0 at distance one and strengthJ at distance two, in the largeU limit |t|, |J|≪U, wheret is the hopping amplitude. As the chemical potential μ is varied, ift=T=0 we find three different phases corresponding to full, half and zero filling fractions. We study the system at low temperatureT≧0 by a method involving a canonical transformation and a functional integral representation. IfT=0 we locate the phase boundaries of the Mott metal-insulator transition for all |J|≪U with upper and lower bounds, show that mean field theory is valid ifJ 0 we have only one sided bounds for the phase boundaries and we can't validate mean field theory in caseJ<0. We introduce a new resummation scheme for low temperature expansions which yields finite and convergent perturbation series and permits us to study issues like the sign problem. Our algorithm gives an optimal canonical transformation for the functional integral such that the expectation of the sign observableS is ≧ exp\(( - c \cdot t \cdot Ve^{ - \frac{\beta }{2}} )\), whereV is the volume and β=T−1.
2 citations