Mott transition

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

Photoluminescent discovery of the impurity–band non-equilibrium current carriers condensation in Ge : Sb

Abstract: Kinetics and magnetic-field investigations of photoluminescent spectra at temperatures between 0.5 and 4.2K in moderately heavily doped Ge:Sb (n D ∼ 10 16 -10 17 cm -3 , below the Mott transition n c = 10 17 cm -3 ) revealed strong changes in the phase diagram of non-equilibrium current carriers compared to the case of pure or lightly doped Ge. The data show that due to the presence of narrow impurity bands at such doping concentrations the non-equilibrium impurity-band current carriers (D-) and free holes (h) condense into the D-H liquid surrounded by the gas phase of D - H-plasma.

Continuous Mott transition in a two-dimensional Hubbard model

Abstract: We investigate a nonmagnetic metal-insulator transition in the 1/5-depleted square lattice Hubbard model at half filling within the eight-site cellular dynamical mean field theory. We find that a metal-insulator transition without any signatures of a first-order transition, a continuous Mott transition, takes place in a certain range of parameters. The nature of the continuous Mott transition is merely a Lifshitz transition driven by the on-site Coulomb interaction. The renormalized matrix elements of hoppings and the spin-spin correlation functions reveal that the physics of this transition is a strong enhancement of the dimerization due to the nonlocal effects of the electron-electron interaction.

Effects of non-local spin fluctuations in the orbital-selective Mott transition

Abstract: Employing the extended dynamical mean field theory (EDMFT) and the quantum Monte Carlo (QMC) method, we investigate the effect of the spatial fluctuations in the two-band Hubbard model with anisotropic bandwidth in the vicinity of the Mott metal-insulator transition. At half filling, we demonstrate that while the inclusion of the non-local spin-spin interaction amounts to enhancing the correlation and suppressing the metallic character, the orbitally selective Mott transition (OSMT) remains stable for various strengths of the non-local correlation. The same is true when the system is doped away from half filling. The OSMT phase is evidenced at low dopant concentration and the simultaneous metallic phase emerges at overdoped regime. From the analysis of the self energy, it follows that the nature of the metallic phase upon doping violates the Fermi liquid character and persists at considerably large doping. Our theory also offers a new perspective for the investigation of the non-local fluctuation in the multi-orbital system within the single-site scheme.

Evolution of possible Weyl semimetal states across the Mott transition in pyrochlore iridates induced by hole doping

Abstract: We study possible Weyl semimetals of strongly correlated electrons by investigating magnetotransport properties in pyrochlore ${R}_{2}{\mathrm{Ir}}_{2}{\mathrm{O}}_{7}$ ($R$ denotes rare-earth ions), choosing three types of $R$ ions to design the exchange coupling scheme between $R\phantom{\rule{4pt}{0ex}}4f$ and Ir $5d$ moments: nonmagnetic Eu $(4{f}^{6})$, isotropic Gd $(4{f}^{7})$, and anisotropic Tb $(4{f}^{8})$. In the doping-induced semimetallic state, distinctive features of magnetoresistance and the Hall effect are observed in $R=\mathrm{Gd}$ and Tb compounds due to the effects of the exchange-enhanced isotropic and anisotropic Zeeman fields, respectively, exemplifying the double-Weyl semimetal and the two-in two-out line-node semimetal as predicted by theories. In particular, the Hall angle of an $R=\mathrm{Gd}$ compound is strongly enhanced to 1.5% just above the critical doping for the Mott transition. Furthermore, an unconventional Hall contribution is discerned for a lower doping regime of the $R=\mathrm{Gd}$ compound, which can be ascribed to the emergence of Weyl points with the field-distorted all-in all-out order state. These findings indicate that the hole-doping-induced Mott transition as well as the characteristic $f\text{\ensuremath{-}}d$ exchange interaction stabilizes versatile topological semimetal states in a wide range of material parameter space.

Field theories of paramagnetic Mott insulators

Abstract: This is a summary of a central argument in recent review articles by the author (Physica A 313, 252 (2002), Annals of Physics 303, 226 (2003), and Rev. Mod. Phys, July 2003). An effective field theory is derived for the low energy spin singlet excitations in a paramagnetic Mott insulator with collinear spin correlations.