Mott transition

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

Electronic, structural, and magnetic properties of transition-metal insulators at very high pressures

Abstract: By simultaneously combining the methods of X-ray diffraction for structural phase transitions and EOS measurements, 57Fe Mossbauer spectroscopy (MS) as a sitesensitive probe, and resistivity measurements for studying insulating-metal transitions we are able to study the effect of extreme pressures and at varying temperature on magnetic and electronic properties of Transition Metal Compounds (TMC). Studies are carried out with specially tailored diamond anvils and diamond anvil cells, reaching pressures beyond 100 GPa. Our studies allow investigating the most basic phenomenon of quantum effect of magnetism in insulating antiferromagnets, the Mott insulators: the high to low spin crossovers, quenching of magnetic moments’ orbital term, and the collapse of the MottHubbard state. Examples of these phenomena will be given in cases of ferrous and ferric oxides, ferrous-halides and the rare-earth iron perovskites.

Parting the Fermi Sea at the Mott Point: Dynamics of Correlated Electrons Reveals the Mechanism Underpinning Mottness

Abstract: By increasing the interaction among conduction electrons, a Fermi-liquid-type metal turns into a Mott insulator. This first-order phase transition should exhibit a regime where the adjacent ground states coexist, leading to electronic phase separation, but the range near $T = 0$ remained unexplored because it is commonly concealed by antiferromangetism. Here we map the genuine low-temperature Mott transition by applying dielectric spectroscopy under pressure to quantum-spin-liquid compounds. The dielectric permittivity uniquely distinguishes all conduction regimes around the Mott point, allowing us to reliably detect insulator-metal phase coexistence below the critical endpoint. Via state-of-the-art theoretical modeling we establish the coupling between segregated metallic puddles as the driving source of a colossal peak in the permittivity reaching $\epsilon_1\approx 10^5$ within the coexistence region. Our results indicate that the observed inhomogeneities are the consequence of phase separation emerging from strong correlation effects inherent to Mottness, suggesting a similar 'dielectric catastrophe' in other correlated materials.

Mott–Hubbard transition in a 2D 3He fluid monolayer

Abstract: We discuss recent observations of the heat capacity and magnetization of a fluid 3He monolayer adsorbed on graphite plated with a bilayer of HD. Approaching the density at which the monolayer solidifies into a 7×7 commensurate solid, we observe an apparent divergence of the effective mass. However, the inferred values of F0a tend to a constant. We interpret this in terms of a Mott–Hubbard transition between a 2D Fermi liquid and a magnetically disordered solid occurring via the Brinkman–Rice–Anderson–Vollhardt scenario.

Mott transition in strongly correlated materials: A realistic modeling using LDA+DMFT

Abstract: OF THE DISSERTATION Mott transition in strongly correlated materials: a realistic modeling using LDA+DMFT by Sahana Murthy Dissertation Director: Professor Gabriel Kotliar We study aspects of the Mott metal-insulator transition in simple models and in real materials. We first investigate the density-driven Mott transition in the degenerate Hubbard model within the framework of dynamical mean-field theory (DMFT). We demonstrate the divergence of compressibility near the finite temperature transition endpoint using quantum Monte Carlo simulations. We show that our results are relevant to the α-γ transition in Cerium. In the latter part of the thesis, we use a combination of density functional methods with local density approximation (LDA) and many body techniques such as DMFT to realistically model two materials with strong correlations. We compute the band structure and spectra of YbRh2Si2 which has an antiferromagnetic ground state. YbRh2Si2 is known to have a strong anisotropy in its magnetic response with respect to its crystal structure. We determine magnetic anisotropy energy of YbRh2Si2 from its total energy. Using LDA+DMFT methods we calculate the spectra and equilibrium volume of Americium. We show that on applying pressure, a Mott metal-insulator transition takes place in Americium which is in accordance with experimental studies.