Mott transition

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

Nonlinear Optics and the Mott Transition in Semiconductors

Abstract: Optical spectra below and above the Mott transition of excitons have to be calculated from the inhomogeneous integral equation for the polarization function including self-energy, screening, and band filling. Results for gap shifts, exciton shift, exciton bleaching, and continuum enhancement are critically reviewed and extended. Optische Spektren unter- und oberhalb des Mott-Ubergangs der Exzitonen mussen mit Hilfe der inhomogenen Integralgleichung fur die Polarisationsfunktion berechnet werden, die Selbstenergie, Abschirmung und Bandfullung einschliest. Ergebnisse fur Gap-Verschiebung, Reduktion der Exziton-Oszillatorstarke und die Verstarkung im Kontinuum werden kritisch referiert und erweitert.

Pseudogap opening and formation of Fermi arcs as an orbital-selective Mott transition in momentum space

Abstract: We present an approach to the normal state of cuprate superconductors which is based on a minimal cluster extension of dynamical mean-field theory. Our approach is based on an effective two-impurity model embedded in a self-consistent bath. The two degrees of freedom of this effective model can be associated to the nodal and antinodal regions of momentum space. We find a metal-insulator transition which is selective in momentum space. At low doping, quasiparticles are destroyed in the antinodal region, while they remain protected in the nodal region, leading to the formation of apparent Fermi arcs. We compare our results to tunneling and angular-resolved photoemission experiments on cuprates. At very low energy, a simple description of this transition can be given using rotationally invariant slave bosons.

Micrometer x-ray diffraction study of VO 2 films: Separation between metal-insulator transition and structural phase transition

Abstract: In order to clarify whether ${\text{VO}}_{2}$ is a Mott insulator or a Peierls insulator, the metal-insulator transition (MIT) and the structural phase transition (SPT) are simultaneously monitored for ${\text{VO}}_{2}$ films by current-voltage curve and diffraction measurements using a synchrotron micro-x-ray beam. In the regime showing a metallic conductivity below the SPT temperature (approximately $70\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$), only the diffraction planes of the monoclinic structure are observed, while planes of the tetragonal structure are absent. This observation reveals the presence of a monoclinic and metal phase between the MIT and the SPT as a characteristic of a Mott insulator.

Physical origins of current and temperature controlled negative differential resistances in NbO 2

Abstract: Negative differential resistance behavior in oxide memristors, especially those using NbO2, is gaining renewed interest because of its potential utility in neuromorphic computing. However, there has been a decade-long controversy over whether the negative differential resistance is caused by a relatively low-temperature non-linear transport mechanism or a high-temperature Mott transition. Resolving this issue will enable consistent and robust predictive modeling of this phenomenon for different applications. Here we examine NbO2 memristors that exhibit both a current-controlled and a temperature-controlled negative differential resistance. Through thermal and chemical spectromicroscopy and numerical simulations, we confirm that the former is caused by a ~400 K non-linear-transport-driven instability and the latter is caused by the ~1000 K Mott metal-insulator transition, for which the thermal conductance counter-intuitively decreases in the metallic state relative to the insulating state. The development of future computation devices will be aided by a better understanding of the physics underlying material behaviors. Using thermoreflectance and spatially resolved X-ray microscopy, Kumar et al. elucidate the origin of two types of negative differential resistance in NbO2 memristors.

Non-Fermi-liquid behavior and double-exchange physics in orbital-selective Mott systems.

Abstract: We study a multiband Hubbard model in its orbital-selective Mott phase, in which localized electrons in a narrow band coexist with itinerant electrons in a wide band. The low-energy physics of this phase is shown to be given by a generalized double-exchange model. The high-temperature disordered phase thus differs from a Fermi liquid, and displays a finite scattering rate of the conduction electrons at the Fermi level, which depends continuously on the spin anisotropy.