Mott transition

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

Exotic phases and quantum phase transitions: model systems and experiments

Abstract: I survey theoretical advances in our understanding of the quantum phases and phase transitions of Mott insulators, and of allied conducting systems obtained by doping charge carriers. A number of new experimental examples of Mott insulators have appeared in recent years, and I critically compare their observed properties with the theoretical expectations.

Buried topological edge state associated with interface between topological band insulator and Mott insulator

Abstract: The electronic structure at the interface between a topological band insulator and a Mott insulator is studied within layer dynamical mean field theory. To represent the bulk phases of these systems, we use the generalized Bernevig-Hughes-Zhang model that incorporates the Hubbard-like on-site Coulomb energy $U$ in addition to the spin-orbit coupling term that causes band inversion. The topological and Mott insulating phases are realized by appropriately choosing smaller and larger values of $U$, respectively. As expected, the interface is found to be metallic because of the localized edge state. When the Coulomb energy in the Mott insulator is close to the critical value, however, this edge state exhibits its largest amplitude deep within the Mott insulator rather than at the interface. This finding corresponds to a new type of proximity effect induced by the neighboring topological band insulator and demonstrates that, as a result of spin-orbit coupling within the Mott insulator, several layers near the interface convert from the Mott insulating phase to a topological insulating phase. Moreover, we argue that the ordinary proximity effect, whereby a Kondo peak is induced in a Mott insulator by neighboring metallic states, is accompanied by an additional reverse proximity effect, by which the Kondo peak gives rise to an enhancement of the density of states in the neighboring metallic layer.

Exciton-biexciton-plasma crossover and formation of optical gain in quantum wires

Abstract: T-shaped GaAs quantum-wire lasers were measured to study origin of laser gain and the exciton Mott transition in one dimension. Origin of laser gain was ascribed not to free excitons, or localized excitons, but to biexciton–exciton population inversion near the threshold, or to the electron–hole (e–h) plasma at a high-density regime well above the threshold. Systematic micro-PL study revealed that dominant PL evolves with e–h density from a sharp free-exciton peak, via a biexciton peak, to an e–h plasma PL band. These demonstrated important roles of biexcitons in the Mott transition and in the initial formation of optical gain. Comparison with microscopic theories raised a question for arguments based on large renormalized band-edge shift before the Mott transition.

Metallic condensation of Wannier-Mott impurity states in lithium-hexamethylphosphoramide glasses

Abstract: A metal to non-metal (MNM) transition observed in frozen solutions of lithium in hexamethylphosphoramide (HMPA) was tentatively interpreted as a Mott transition in which localized Wannier-type impurity states were the source of electrons in the metallic state. In this paper this assertion is examined in greater detail by calculating critical densities (nc) on the basis of a scaled (variational) form of Mott's original criterion for the onset of localization in a dielectrically screened Coulomb potential, and also on the basis of the Hubbard tight-binding model. Mott's model for the transition is based upon the screening properties of a freely propagating gas of metallic electrons. In the Hubbard regime, however, the phenomenon is viewed from the tight-binding limit; the transition from localized to delocalized states occurs when the bandwidth (Δ) of a regular lattice of isolated centres exceeds the value of the intra-atomic Coulombic repulsion integral (U) associated with electron correlation.Both electro...

Second Superconducting Transition Driven by Charge Density Wave

Abstract: Instability of charge density wave can drive successive superconducting transitions. The transition at a lower temperature can be detected by the softening of phonons, whose symmetry is compatible with the symmetry of the product of the two superconducting order parameters. It is argued that the second transition is responsible for tiny anomalies around T c2 ≈35 K in high-temperature superconductors YBa 2 Cu 3 O 7 with superconducting critical temperature T c ≈90 K. It is also argued that the anisotropic Cooper pairing is responsible for high-temperature superconductivity not only in YBa 2 Cu 3 O 7 but also in the other cuprate oxides.