Mott transition

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

Disorder-induced enhancement of the persistent current for strongly interacting electrons in one-dimensional rings

Abstract: We show that disorder increases the persistent current of a half-filled one-dimensional Hubbard-Anderson ring at strong interaction. This unexpected effect results from a perturbative expansion starting from the strongly interacting Mott insulator ground state. The analytical result is confirmed and extended by numerical calculations.

Anomalous Metal Phase Emergent on the Verge of an Exciton Mott Transition.

Abstract: We investigate the exciton Mott transition (EMT) by using optical pump-terahertz probe spectroscopy on GaAs, with realizing the condition of Mott's gedanken experiment by the resonant excitation of 1s excitons. We show that an anomalous metallic phase emerges on the verge of the EMT as manifested by a peculiar enhancement of the quasiparticle mass and scattering rate. From the temperature and density dependence, the observed anomaly is shown to originate from the electron-hole (e-h) correlation which becomes prominent at low temperatures, possibly suggesting a precursor of e-h Cooper pairing.

Magnetism in rare-earth metals and rare-earth intermetallic compounds

Abstract: Some of our recent local spin density electronic structure calculations for a number of ferromagnetic rare-earth systems are reviewed. A simplified model of the level densities for rare-earth (R) transition metal (M) intermetallic compounds, RmMn, is used to describe in a simple way the main features of their basic electronic structure. Explicit calculations for LuFe2 and RFe2 (R = Gd-Yb) systems are presented, where a method to treat simultaneously the localized 4f and the conduction electron spin magnetism is introduced. Thereby it becomes possible to calculate the KRM exchange coupling constant. This method is also used to study theoretically the permanent magnet material Nd2Fe14B. The electronic structure of the anomolous ferromagnets CeFe2 and CeCo5 is discussed and an induced 4f itinerant magnetism is predicted. The γ-α transition in cerium metal is considered, and result from calculations including orbital polarization are presented, where a volume collapse of 10% is obtained. On one side of the transition the 4f electrons are calculated to be essentially non-bonding (localized) and on the other side they are found to contribute to the metallic bonding and this difference in behaviour gives rise to the volume collapse. Recent calculations by Wills, Eriksson and Boring (Ref. [5]) for the crystal structure changes in cerium metal under high pressure are discussed. Their successful results imply an itinerant picture for the 4f electrons in α-cerium. Consequently this strongly supports the view that the γ-α phase transformation is caused by a Mott transition of the 4f electrons.

Observation of the exciton Mott transition in the photoluminescence of coupled quantum wells

Abstract: Indirect excitons in coupled quantum wells have long radiative lifetimes and form a cold quasi-two-dimensional population suitable for studying collective quantum effects. Here we report the observation of the exciton Mott transition from an insulating (excitons) to a conducting (ionized electron-hole pairs) phase, which occurs gradually as a function of carrier density and temperature. The transition is inferred from spectral and time-resolved photoluminescence measurements around a carrier density of $2\ifmmode\times\else\texttimes\fi{}{10}^{10}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$ and temperatures of 12--16 K. An externally applied electric field is employed to tune the dynamics of the transition via the quantum-confined Stark effect. Our results provide evidence of a gradual nature of the exciton Mott transition.