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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, the electric-field dependence of the delay time is analyzed in terms of a phenomenological model for typical one-dimensional (1D) Mott insulators, and the threshold electric field for the breakdown, defined as a field above which the differential resistance becomes negative, has been found to increase exponentially with decreasing temperature.
Abstract: Dielectric breakdown phenomena accompanied by characteristic time delay and subsequent negative differential resistance effect have been observed for typical one-dimensional (1D) Mott insulators, ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}$ and ${\mathrm{SrCuO}}_{2}.$ In the both compounds, the threshold electric-field for the breakdown, defined as a field above which the differential resistance becomes negative, has been found to increase exponentially with decreasing temperature. This result is similar to the case of charge-density-wave depinning, and indicates the collective nature of charge dynamics in these 1D systems. The electric-field dependence of the delay time is analyzed in terms of a phenomenological model.

81 citations

Journal ArticleDOI
04 Oct 2007-Nature
TL;DR: This work argues that a key pseudogap phenomenon—fluctuating superconductivity occurring substantially above the transition temperature—could be induced by the proximity of a Mott-insulating state and finds that a fluctuating regime develops as t/U decreases and the role of Coulomb correlations increases.
Abstract: Behaviour similar to that of the 'pseudogap' regime in unconventional superconductors is reported in a family of superconducting organic molecular metals. The 'pseudogap' signature that was measured (fluctuating superconductivity above the critical temperature) is most pronounced in those samples that are close to being in a Mott insulating state, suggesting a close relationship between the two phenomena. On cooling through the transition temperature Tc of a conventional superconductor, an energy gap develops as the normal-state charge carriers form Cooper pairs; these pairs form a phase-coherent condensate that exhibits the well-known signatures of superconductivity: zero resistivity and the expulsion of magnetic flux (the Meissner effect1). However, in many unconventional superconductors, the formation of the energy gap is not coincident with the formation of the phase-coherent superfluid. Instead, at temperatures above the critical temperature a range of unusual properties, collectively known as ‘pseudogap phenomena’, are observed2. Here we argue that a key pseudogap phenomenon—fluctuating superconductivity occurring substantially above the transition temperature—could be induced by the proximity of a Mott-insulating state. The Mott-insulating state in the κ-(BEDT-TTF)2X organic molecular metals3,4,5 can be tuned, without doping, through superconductivity into a normal metallic state as a function of the parameter t/U, where t is the tight-binding transfer integral characterizing the metallic bandwidth and U is the on-site Coulomb repulsion. By exploiting a particularly sensitive probe of superconducting fluctuations, the vortex-Nernst effect, we find that a fluctuating regime develops as t/U decreases and the role of Coulomb correlations increases.

80 citations

Journal ArticleDOI
TL;DR: In this paper, angle-resolved photoemission spectroscopy was used to make direct experimental determinations of intra-and intercell coupling parameters as well as Mott correlations and gap sizes.
Abstract: We studied Sr${}_{2}$IrO${}_{4}$ and Sr${}_{3}$Ir${}_{2}$O${}_{7}$ using angle-resolved photoemission spectroscopy, making direct experimental determinations of intra- and intercell coupling parameters as well as Mott correlations and gap sizes. The results are generally consistent with LDA+$U$+spin-orbit coupling calculations, though the calculations missed the momentum positions of the dominant electronic states and neglected the importance of intercell coupling on the size of the Mott gap. The calculations also ignore the correlation-induced spectral peak widths, which are critical for making a connection to activation energies determined from transport experiments. The data indicate a dimensionality-controlled Mott transition in these 5$d$ transition-metal oxides.

80 citations

Journal ArticleDOI
TL;DR: In this paper, three regimes of the Mott transition characterized by classical, marginally quantum, and quantum were studied, and it was shown that the transition is always at the upper critical dimension irrespective of the spatial dimensions.
Abstract: We study three regimes of the Mott transitions characterized by classical, marginally quantum, and quantum. In the classical regime, the quantum degeneracy temperature is lower than the critical temperature of the Mott transition ${T}_{c}$, below which the first-order transition occurs. The quantum regime describes the ${T}_{c}=0$ boundary of the continuous transition. The marginal quantum region appears sandwiched by these two regimes. The classical transition is described by the Ising universality class. However, the Ginzburg-Landau-Wilson scheme breaks down when the quantum effects dominate. The marginal quantum critical region is categorized to an unusual universality class, where the order parameter exponent $\ensuremath{\beta}$, the susceptibility exponent $\ensuremath{\gamma}$, and the field exponent $\ensuremath{\delta}$ are given by $\ensuremath{\beta}=d∕2$, $\ensuremath{\gamma}=2\ensuremath{-}d∕2$, and $\ensuremath{\delta}=4∕d$, respectively, with $d$ being the spatial dimensionality. It is shown that the transition is always at the upper critical dimension irrespective of the spatial dimensions. Therefore the mean-field exponents and the hyperscaling description become both valid at any dimension. The obtained universality classes agree with the recent experimental results on the Mott criticality in organic conductors such as $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{ET})}_{2}\mathrm{Cu}[\mathrm{N}{(\mathrm{C}\mathrm{N})}_{2}]\mathrm{Cl}$ and transition-metal compounds such as ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$. The marginal quantum criticality is characterized by the critically enhanced electron-density fluctuations at small wave number. The characteristic energy scale of the density fluctuation extends to the order of the Mott gap in contrast to the spin and orbital fluctuation scales and causes various unusual properties. The mode coupling theory shows that the marginal quantum criticality further generates non-Fermi-liquid properties in the metallic side. The effects of the long-range Coulomb force in the filling-control Mott transition are also discussed. A mechanism of high-temperature superconductivity emerges from the density fluctuations at small wave number inherent in the marginal quantum criticality of the Mott transition. The mode coupling theory combined with the Eliashberg equation predicts the superconductivity of the ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ symmetry with the transition temperature of the correct order of magnitude for the realistic parameters for the cuprate superconductors. Experimental results on the electron differentiations established in the angle-resolved photoemission experiments are favorably compared with the present prediction. The tendency for the spatial inhomogeneity is a natural consequence of this criticality.

80 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of the orbital degrees of freedom on the reduction of dimensionality of the condensed matter is discussed. But the authors mainly concentrate on other phenomena, which are in the focus of the modern condensed matter physics.
Abstract: In the present review different effects related to the orbital degrees of freedom are discussed. Leaving aside such aspects as the superexchange mechanism of the cooperative Jahn-Teller distortions and different properties of "Kugel-Khomskii"-like models, we mostly concentrate on other phenomena, which are in the focus of the modern condensed matter physics. After a general introduction we start with the discussion of the concept of effective reduction of dimensionality due to orbital degrees of freedom and consider such phenomena as the orbitally-driven Peierls effect and the formation of small clusters of ions in the vicinity of a Mott transition, which behave like "molecules" embedded in a solid. The second large section is devoted to the orbital-selective effects such as the orbital-selective Mott transition and the suppression of magnetism due to the fact that part of the orbitals start to form singlet molecular orbitals. At the end the rapidly growing field of the so-called "spin-orbit-dominated" transition metal compounds is briefly reviewed including such topics as the interplay between the spin-orbit coupling and the Jahn-Teller effect, the formation of the spin-orbit driven Mott and Peierls states, the role of orbital degrees of freedom in generation of the Kitaev exchange coupling, and the singlet (excitonic) magnetism in $4d$ and $5d$ transition metal compounds.

79 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202334
202271
202165
202064
201968
201871