Mott transition

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

Doping induced Mott collapse and possible density wave instabilities in (Sr1−xLax)3Ir2O7

Abstract: The path from a Mott insulating phase to high temperature superconductivity encounters a rich set of unconventional phenomena involving the insulator-to-metal transition (IMT), such as emergent electronic orders and pseudogaps, that ultimately affect the condensation of Cooper pairs. A huge hindrance to understanding the origin of these phenomena is the difficulty in accessing doping levels near the parent state. The Jeff = 1/2 Mott state of the perovskite strontium iridates has revealed intriguing parallels to the cuprates, with the advantage that it provides unique access to the Mott transition. Here, we exploit this accessibility to study the IMT and the possible nearby electronic orders in the electron-doped bilayer iridate (Sr1 − xLax)3Ir2O7. Using spectroscopic imaging scanning tunneling microscopy, we image the La dopants in the top as well as the interlayer SrO planes. Surprisingly, we find a disproportionate distribution of La between these layers with the interlayer La being primarily responsible for the IMT. This reveals the distinct site-dependent effects of dopants on the electronic properties of bilayer systems. Electron doping also results in charge reordering. We find unidirectional electronic order concomitant with the structural distortion known to exist in this system. Intriguingly, similar to the single layer iridate, we also find local resonant states forming a checkerboard-like pattern trapped by La. This suggests that multiple charge orders may exist simultaneously in Mott systems, even with only one band crossing the Fermi energy.

Ultrafast Mott transition driven by nonlinear electron-phonon interaction

Abstract: Nonlinear phononics holds the promise for controlling properties of quantum materials on the ultrashort timescale. Using nonequilibrium dynamical mean-field theory, we solve a model for the description of organic solids, where correlated electrons couple nonlinearly to a quantum phonon mode. Unlike previous works, we exactly diagonalize the local phonon mode within the noncrossing approximation to include the full phononic fluctuations. By exciting the local phonon in a broad range of frequencies near resonance with an ultrashort pulse, we show it is possible to induce a Mott insulator-to-metal phase transition. Conventional semiclassical and mean-field calculations, where the electron-phonon interaction decouples, underestimate the onset of the quasiparticle peak. This fact, together with the nonthermal character of the photoinduced metal, suggests a leading role of the phononic fluctuations and of the dynamic nature of the state in the vibrationally induced quasiparticle coherence.

SU(3) fermions on the honeycomb lattice at 1/3 filling

Abstract: $\mathrm{SU}(N)$ symmetric fermions on a lattice, which can be realized in ultracold-atom-based quantum simulators, have very promising prospects for realizing exotic states of matter. Here we present the ground-state phase diagram of the repulsive SU(3) Hubbard model on a honeycomb lattice at 1/3 filling obtained from infinite projected entangled pair states tensor network calculations. In the strongly interacting limit the ground state has plaquette order. Upon decreasing the interaction strength $U/t$ we find a first-order transition at $U/t=7.2(2)$ into a dimerized, color-ordered state, which extends down to $U/t=4.5(5)$, at which the Mott transition occurs and the ground state becomes uniform. Our results may serve as a prediction and benchmark for future quantum simulators of SU(3) fermions.

Superfluid fermi gas in a 1D optical lattice.

Abstract: We calculate the superfluid transition temperature for a two-component 3D Fermi gas in a 1D tight optical lattice and discuss a dimensional crossover from the 3D to quasi-2D regime. For the geometry of finite size discs in the 1D lattice, we find that even for a large number of atoms per disc the critical effective tunneling rate for a quantum transition to the Mott insulator state can be large compared to the loss rate caused by three-body recombination. This allows the observation of the Mott transition, in contrast to the case of Bose-condensed gases in the same geometry.

Magnetically driven orbital-selective insulator–metal transition in double perovskite oxides

Abstract: Interaction-driven metal–insulator transitions or Mott transitions are widely observed in condensed matter systems. In multi-orbital systems, many-body physics is richer in which an orbital-selective metal–insulator transition is an intriguing and unique phenomenon. Here we use first-principles calculations to show that a magnetic transition (from paramagnetic to long-range magnetically ordered) can simultaneously induce an orbital-selective insulator–metal transition in rock-salt ordered double perovskite oxides A2BB′O6, where B is a non-magnetic ion (Y3+ and Sc3+) and B′ a magnetic ion with a d3 electronic configuration (Ru5+ and Os5+). The orbital-selectivity originates from geometrical frustration of a face-centered-cubic lattice on which the magnetic ions B′ reside. Including realistic structural distortions and spin-orbit interaction do not affect the transition. The predicted orbital-selective transition naturally explains the anomaly observed in the electric resistivity of Sr2YRuO6. Implications of other available experimental data are also discussed. This work shows that by exploiting geometrical frustration on non-bipartite lattices, new electronic/magnetic/orbital-coupled phase transitions can occur in correlated materials that are in the vicinity of metal–insulator phase boundary. First-principle calculations shed new light on orbital-selective Mott transitions in magnetic perovskites, providing new insight and explaining existing data. A Mott transition is a metal–insulator transition whereby electric-field screening causes the potential felt by electrons to become strongly peaked, making the electrons localized. In multi-orbital systems an orbital-selective Mott transition can occur: electrons become localized on some orbitals but remain itinerant on the others. Hanghui Chen from New York University Shanghai in China uses first-principle calculations to show that a magnetic transition can induce an orbital-selective Mott transition in an ordered double perovskite oxide, in which the occurrence of long-range magnetic order makes electrons in one orbital metallic while leaving the others insulating. This is related to geometrical frustration in the magnetic lattice, and structural distortions and spin-orbit interactions do not affect the transition.