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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 Mott transition was revealed in the non-distorted monoclinic nanodomain between $55-63^oC, and the distortion-assisted structural phase transition above $60^ oC.
Abstract: $VO_2$ undergoes the insulator-metal transition (IMT) and monoclinic-rutile structural phase transition (SPT) near $67^oC$. The IMT switching has many applications. However, there is an unresolved issue whether the IMT is a Mott transition or a Peierls transition. This complication is caused by metal and insulator coexistence, which is an inherent property of the IMT region. Thus, the acquired data in the IMT region are averaged over the two phases in many experiments. We overcome the issue by probing the electronic state of the monoclinic structure and by introducing a model that accounts for the coexisting phases. We reveal the Mott IMT in the non-distorted monoclinic nanodomain between $55-63^oC$, and the distortion-assisted SPT above $60^oC$.
2 citations
TL;DR: In this article, the effects of the inter-site interactions on the exciton Mott transition were investigated using the extended Hubbard model for the electron-hole systems, which incorporates both repulsive (electron-electron and hole-hole) and attractive (electRON−hole) intersite interactions in addition to the on-site Hubbard interactions.
Abstract: We investigate the effects of the inter-site interactions on the exciton Mott transition using the extended Hubbard model for the electron–hole systems, which incorporates both repulsive (electron–electron and hole–hole) and attractive (electron–hole) inter-site interactions in addition to the on-site Hubbard interactions. The analysis by means of the extended dynamical mean-field theory clarifies that the inter-site interactions do not change the nature of the exciton Mott transition in high dimensions but tend to stabilize the metallic electron–hole plasma state, when the inter-site repulsive and attractive interactions have the same strength. In contrast, we find that small difference between the repulsive and attractive interactions dramatically changes the electronic states. This small perturbation strongly enhances fluctuations of the mass density, and drives the system to the insulator with the strong fluctuations of the mass density wave. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
2 citations
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TL;DR: In this article, a microcavity with strong-and weak-couplings co-existing in orthogonal linear polarizations was used to measure the electronic gain in the matter media of a polariton laser.
Abstract: Microcavity exciton polariton systems can have a wide range of macroscopic quantum effects that may be turned into better photonic technologies. Polariton Bose-Einstein condensation (BEC) and photon lasing have been widely accepted in the limits of low and high carrier densities, but identification of the expected Bardeen-Cooper-Schrieffer (BCS) state at intermediate densities remains elusive. While all three phases feature coherent photon emission, essential differences exist in their matter media. Most studies to date characterize only the photon field. Here, using a microcavity with strong- and weak-couplings co-existing in orthogonal linear polarizations, we directly measure the electronic gain in the matter media of a polariton laser, demonstrating a BCS-like polariton laser above the Mott transition density. Theoretical analysis reproduces the absorption spectra and lasing frequency shifts, revealing an electron distribution function characteristic of a polariton BCS state but modified by incoherent pumping and dissipation.
2 citations
TL;DR: In this paper, the optical, Raman, and ac Hall response of the doped Mott insulator within the dynamical mean-field theory was studied for strongly correlated electron systems, and the role of low-energy coherence (FL) or incoherence (non-FL) in determining the finite frequency response of strongly correlated metals in $d=\ensuremath{\infty}$ was discussed.
Abstract: We study the optical, Raman, and ac Hall response of the doped Mott insulator within the dynamical mean-field theory $(d=\ensuremath{\infty})$ for strongly correlated electron systems. The occurrence of the isosbectic point in the optical conductivity is shown to be associated with the frequency dependence of the generalized charge susceptibility. We compute the Raman response, which probes the fluctuations of the ``stress tensor,'' and show that the scattering is characterized by appreciable incoherent contributions. The calculated ac Hall constant and Hall angle also exhibit the isosbectic points. These results are also compared with those obtained for a non-FL metal in $d=\ensuremath{\infty}.$ The role of low-energy coherence (FL) or incoherence (non-FL) in determining the finite frequency response of strongly correlated metals in $d=\ensuremath{\infty}$ is discussed in detail. As an application of interest, we compute the dielectric figure-of-merit (DFOM), a quantity that is of potential importance for microwave device applications. We demonstrate explicitly that systems near the filling driven Mott transition might be good candidates in this respect, and discuss the influence of real-life factors on the DFOM.
2 citations
TL;DR: In this paper, the authors explored the transport properties of Y 1− x A x TiO 3 (A=Ca, Sr and Ba) as a function of 3d band filling n (=1− x ) by measurement of X-ray diffraction, resistivity and thermopower.
2 citations