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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 experimental data obtained on high-quality single crystals of iron monosilicide allow us to conclude in favor of the Mott-Hubbard scenario of metal-insulator transition with the on-site Coulomb interaction U in vicinity of the critical value U⩽Uc≈3D (D- is the band halfwidth).
Abstract: The study of DC-, low and radiofrequency AC-conductivity in combination with Hall and Seebeck coefficients and magnetic measurements have been carried out at temperatures 1.6–300 K, in magnetic field up to 12 T in the so-called Kondo-insulator compound-narrow-gap semiconductor FeSi. The experimental data obtained on high-quality single crystals of iron monosilicide allow us to conclude in favor of Mott–Hubbard scenario of metal–insulator transition with the on-site Coulomb interaction U in vicinity of the critical value U⩽Uc≈3D (D- is the band half-width). The estimation of microscopic parameters provides additional arguments in favor of the spin polarons formation and dramatic renormalization of the intra-gap electronic density of states in FeSi at temperatures below 100 K. In the temperature interval T⩽Tc≈15 K an onset of the coherent spin fluctuations occurs in the cubic lattice of FeSi resulting in the formation of ferromagnetic microregions (about 10 A in size). When the temperature decreases below Tm≈7 K an interaction between these ferromagnetic particles causes a mictomagnetic transition in this low carrier density ( 10 17 –10 18 cm −3 ) d-electron material.
2 citations
TL;DR: In this paper, a theory of the Meissner effect due to Cooper pairs between Bloch electrons is presented in the gauge-invariant form by including effects of strong electron correlation, applied to analyzing observed penetration depth λ( T ) of YBa 2 Cu 3 O 7 with T c ≈90 K.
Abstract: A theory of the Meissner effect due to Cooper pairs between Bloch electrons is presented in the gauge-invariant form by including effects of strong electron correlation. The theory is applied to analyzing observed penetration depth λ( T ) of YBa 2 Cu 3 O 7 with T c ≈90 K. Observed λ(0)≈1400 A can be explained, if the effective mass of quasiparticles is about ten times as large as the electron mass. By assuming that the superconducting gap is as large as 2 e G / T c ≈8, as implied by many experiments, it is shown that anisotropic Cooper pairs between heavy electrons in the Mott-transition region can explain the observed λ( T ) above 35 K. One of the possible scenarios to explain the data below 35 K is a successive superconducting transition at T c2 ≈35 K, as implied by small but sharp anomalies in the transverse nuclear quadrupole relaxation rate. It is argued that the complete gap is open below T c2 ≈35 K.
2 citations
TL;DR: In this article, a planar Mott thin-film device with high-resolution wide-field microscopy and electric transport measurements was used to study resistive switching in a Mott insulator, which undergoes a thermally driven metal-to-insulator transition.
Abstract: Resistive switching---the current- and voltage-induced change of electrical resistance---is at the core of memristive devices, which play an essential role in the emerging field of neuromorphic computing. This study is about resistive switching in a Mott insulator, which undergoes a thermally driven metal-to-insulator transition. Two distinct switching mechanisms are reported for such a system: electric-field-driven resistive switching and electrothermal resistive switching. The latter results from an instability caused by Joule heating. Here, we present the visualization of the reversible resistive switching in a planar $\mathrm{V}$${}_{2}$$\mathrm{O}$${}_{3}$ thin-film device using high-resolution wide-field microscopy in combination with electric transport measurements. We investigate the interaction of the electrothermal instability with the strain-induced spontaneous phase separation in the $\mathrm{V}$${}_{2}$$\mathrm{O}$${}_{3}$ thin film at the Mott transition. The photomicrographs show the formation of a narrow metallic filament with a minimum width $\ensuremath{\lesssim}500$ nm. Although the filament formation and the overall shape of the current-voltage characteristics (IVCs) are typical of an electrothermal breakdown, we also observe atypical effects such as oblique filaments, filament splitting, and hysteretic IVCs with sawtoothlike jumps at high currents in the low-resistance regime. We are able to reproduce the experimental results in a numerical model based on a two-dimensional resistor network. This model demonstrates that resistive switching in this case is indeed electrothermal and that the intrinsic heterogeneity is responsible for the atypical effects. This heterogeneity is strongly influenced by strain, thereby establishing a link between switching dynamics and structural properties.
2 citations
TL;DR: In this paper, the authors measured the density of states of Ca3Ru2O7 across the transition by tunneling spectroscopy, which is possible because the compound remains poorly conducting even in its non-metallic phase at low temperatures.
2 citations
TL;DR: In this paper, the divergence in the electronic self-energy in an electron-phonon system with the on-site Coulomb repulsion was investigated, and the localization due to U and/or the phonon-mediated attractive interaction was studied.
Abstract: By investigating the divergence in the electronic self-energy in an electron-phonon system with the on-site Coulomb repulsionU, we study the localization due toU and/or the phonon-mediated attractive interactionV. In addition to the generalization of the Mott transition in the Hubbard model by includingV, particular attention is paid to the localization due to the confinement by local phonons occurring at finite energies which may be called as the dynamical localization.
2 citations