Mott transition

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

A New Scenario on the Metal–Insulator Transition in VO2

Abstract: The metal–insulator transition in VO 2 was investigated using the three-band Hubbard model, in which the degeneracy of the 3 d orbitals, the on-site Coulomb and exchange interactions, and the effec...

Comparative analysis of models for the α − γ phase transition in cerium: A DFT+DMFT study using Wannier orbitals

Abstract: We clarify the orbital mechanism of the $\ensuremath{\alpha}\text{\ensuremath{-}}\ensuremath{\gamma}$ transition in cerium. First we built an $sdf$ Wannier orbital basis to describe the electronic structure of cerium. Second, we use this basis to study the relative role of several orbital hoppings upon compression of cerium. Third, we use DFT + DMFT calculations to quantify the impact of these hoppings on electronic structure. Our conclusion is that upon compression of $\ensuremath{\gamma}$ cerium, the change of hybridization is due to both interatomic $ff$ and $fd$ hopping integrals. In particular, neglecting $ff$ hoppings leads to an important renormalization of both the hybridization and the quasiparticle peak. Thus, neither the Kondo volume collapse nor the Mott transition model are sufficient to describe the isostructural transition in cerium.

Born effective charge reversal and metallic threshold state at a band insulator-Mott insulator transition

Abstract: We study the quantum phase transition between a band (“ionic”) insulator and a Mott-Hubbard insulator, realized at a critical value in a bipartite Hubbard model with two inequivalent sites, whose on-site energies differ by an offset . The study is carried out both in D=1 and D=2 (square and honeycomb lattices), using exact Lanczos diagonalization, finite-size scaling, and Berry's phase calculations of the polarization. The Born effective charge jump from positive infinity to negative infinity previously discovered in D=1 by Resta and Sorella is confirmed to be directly connected with the transition from the band insulator to the Mott insulating state, in agreement with recent work of Ortiz et al. In addition, symmetry is analysed, and the transition is found to be associated with a reversal of inversion symmetry in the ground state, of magnetic origin. We also study the D=1 excitation spectrum by Lanczos diagonalization and finite-size scaling. Not only the spin gap closes at the transition, consistent with the magnetic nature of the Mott state, but also the charge gap closes, so that the intermediate state between the two insulators appears to be metallic. This finding, rationalized within Hartree-Fock as due to a sign change of the effective on-site energy offset for the minority spin electrons, underlines the profound difference between the two insulators. The band-to-Mott insulator transition is also studied and found in the same model in D=2. There too we find an associated, although weaker, polarization anomaly, with some differences between square and honeycomb lattices. The honeycomb lattice, which does not possess an inversion symmetry, is used to demonstrate the possibility of an inverted piezoelectric effect in this kind of ionic Mott insulator.