Topic
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 paper, the ground state of the half-filled Hubbard model is discussed as a function of t and correlation strength U, where t and t' are the hopping amplitudes between nearest and next-nearest neighbors.
Abstract: We investigate the paramagnetic-metal-to-antiferromagnetic-metal and antiferromagnetic-metal-to- antiferromagnetic-insulator transitions using a slave-boson mean-field theory. To this effect, we discuss the ground state of the half-filled Hubbard model as a function of t'/t and correlation strength U, where t and t' are the hopping amplitudes between nearest and next-nearest neighbors, respectively. The metal-insulator transition at a critical U_{MIT} is of second order for small levels of magnetic frustration, t'/t 0.06. The insulator is always antiferromagnetically ordered, while the metal exhibits a second-order transition from a paramagnetic to an antiferromagnetic state up to t'/t=0.14, as U is increased. We also contrast these findings with what we obtain in Hartree-Fock approximation.
15 citations
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TL;DR: In this paper, the effects of Anderson localization, exchange and correlation in the Hubbard model are included in this model, and the vanishing of ionization energy triggering a Mott transition is observed within the one-electron approximation.
15 citations
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TL;DR: It is found that 3s photoemission provides information about local magnetic moments created by 3d electrons in these materials, which are smaller by about 15-25% in the metal phase than those in the insulator phases.
Abstract: The 3s and 3p photoelectrons have been measured in pure and Cr-doped V 2 O 3 , in the antiferromagnetic insulator, paramagnetic metal, and paramagnetic insulator phases. It is found that 3s photoemission provides us with information about local magnetic moments created by 3d electrons in these materials. They are smaller by about 15-25% in the metal phase than those in the insulator phases. The observed results are discussed in conjunction with the Mott transition and the importance of the spin-fluctuation effect is emphasized
15 citations
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TL;DR: This paper summarizes earlier results on unconventional metallic fulleride phases as well as the newly discovered expanded fulleride superconductors and concentrates on infrared and optical spectroscopy which is very well suited to follow metallicity and phase transitions in this class of substances.
Abstract: Metallic salts formed from fullerenes became popular because of their superconducting properties with a relatively high transition temperature, and were initially regarded as conventional metals and superconductors. Recently, owing to improved synthetic methods and a renewed interest in the study of their physical properties, many of them were found to exhibit exotic metallic and superconducting phases. In this paper, we summarize earlier results on unconventional metallic fulleride phases as well as the newly discovered expanded fulleride superconductors. The proximity of the Mott transition, a typical solid-state effect, results in molecular crystals, where molecular spectroscopic methods prove very successful. We concentrate on infrared and optical spectroscopy which is very well suited to follow metallicity and phase transitions in this class of substances.
15 citations
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TL;DR: In this paper, the authors examined a forward bias activated differential capacitance response of GaInP/AlGaInP based multi-quantum well laser diodes to trace the presence of excitons using electrical measurements.
Abstract: Mostly, optical spectroscopies are used to investigate the physics of excitons, whereas their electrical evidences are hardly explored. Here, we examined a forward bias activated differential capacitance response of GaInP/AlGaInP based multi-quantum well laser diodes to trace the presence of excitons using electrical measurements. Occurrence of “negative activation energy” after light emission is understood as thermodynamical signature of steady state excitonic population under intermediate range of carrier injections. Similar corroborative results are also observed in an InGaAs/GaAs quantum dot laser structure grown by molecular beam epitaxy. With increasing biases, the measured differential capacitance response slowly vanishes. This represents gradual Mott transition of an excitonic phase into an electron-hole plasma in a GaInP/AlGaInP laser diode. This is further substantiated by more and more exponentially looking shapes of high energy tails in electroluminescence spectra with increasing forward bias, which originates from a growing non-degenerate population of free electrons and holes. Such an experimental correlation between electrical and optical properties of excitons can be used to advance the next generation excitonic devices.
15 citations