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Mott transition

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


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01 Jan 2012
TL;DR: In this article, the effect of polarity mismatch on the initial growth of 3d7(t6 2ge 1 g) systems with spin (S=1/2) and orbital degeneracies was investigated.
Abstract: Strongly correlated electron systems, particularly transition metal oxides, have been a focus of condensed matter physics for more than two decades since the discovery of high-temperature superconducting cuprates. Diverse competing phases emerge, spanning from exotic magnetism to unconventional superconductivity, in proximity to the localized-itinerant transition of Mott insulators. While studies were concentrated on bulk crystals, the recent rapid advance in synthesis has enabled fabrication of high-quality oxide heterostructures, offering a new route to create novel artificial quantum materials. This dissertation details the investigation on ultrathin films and heterostructures of 3d7(t6 2ge 1 g) systems with spin (S=1/2) and orbital degeneracies. Perovskite RNiO3 (R = rare earth) was chosen as a representative model, since its Ni 3+ valence corresponds to the low-spin 3d7 configuration. The heteroepitaxial growth of RNiO3 ultrathin films and heterostructures was studied by laser molecular beam epitaxy. To achieve a layer-by-layer growth mode crucial for stabilizing the proper stoichiometry and creating sharp interfaces, a fast pumping plus interruption growth method was developed. In addition to conventional transport measurement, resonant x-ray absorption spectroscopy was used to characterize the resulting electronic structures. The results demonstrate that the effect of polarity mismatch on the initial growth may lead to a chemical pathway for compensating the dipolar field. By utilizing the x-ray linear dichroic effect, an asymmetric heteroepitaxial straininduced d orbital response in LaNiO3 was revealed. Moreover, the interfacial lattice constraint was found to modulate the Ni-O covalency in RNiO3 by simultaneously tuning the Madelung energy and the p−d hybridization, leading to a self-doped mechanism that controls the collective phase behavior in NdNiO3. The electronic reconstructions in correlated quantum wells were also investigated in superlattices of LaNiO3/LaAlO3. In proximity to the confinement limit, a Mott-type metal-insulator transition was observed with tendency towards charge ordering as a competing ground state. The interfacial Ni-O-Al bond was found to highly suppress the apical ligand hole density and result in confinement-induced orbital polarization. The key role of the interfacial boundary in selecting the many-body electronic ground state was directly demonstrated in quantum wells of NdNiO3. This dissertation is approved for recommendation to the Graduate Council Dissertation Director: —————————————————————————– Dr. Jak Chakhalian, Ph.D. Dissertation Committee: —————————————————————————– Dr. Laurent Bellaiche, Ph.D. —————————————————————————– Dr. Surendra P. Singh, Ph.D. —————————————————————————– Dr. Paul Thibado, Ph.D. —————————————————————————– Dr. Ryan Tian, Ph.D. Dissertation Duplication Release I hereby authorize the University of Arkansas Libraries to duplicate this dissertation when needed for research and/or scholarship.

6 citations

Journal ArticleDOI
TL;DR: In this paper, the Mott transition in Hubbard models with a degenerate band on different 3-dimensional lattices was analyzed and it was shown that frustration increases Uc, compared to bipartite systems.

6 citations

Journal ArticleDOI
TL;DR: In this article, the filling-interaction phase diagram of the single band Hubbard model at zero temperature is presented, which can be generalized to any particle filling and can be extended to finite temperature.
Abstract: The local moment approach (LMA) has presented itself as a powerful semianalytical quantum impurity solver (QIS) in the context of the dynamical mean-field theory (DMFT) for the periodic Anderson model and it correctly captures the low-energy Kondo scale for the single impurity model, having excellent agreement with the Bethe ansatz and numerical renormalization group (NRG) results. However, the most common correlated lattice model, the Hubbard model, has not been explored well within the LMA+DMFT framework beyond the insulating phase. Here in our work, within the framework we complete the filling-interaction phase diagram of the single band Hubbard model at zero temperature. Our formalism is generic to any particle filling and can be extended to finite temperature. We contrast our results with another QIS, namely the iterated perturbation theory (IPT) and show that the second spectral moment sum rule improves better as the Hubbard interaction strength grows stronger in LMA, whereas it severely breaks down after the Mott transition in IPT. For the metallic case, the Fermi liquid (FL) scaling agreement with the NRG spectral density supports the fact that the FL scale emerges from the inherent Kondo physics of the impurity model. We also show that, in the metallic phase, the FL scaling of the spectral density leads to universality which extends to infinite frequency range at infinite correlation strength (strong coupling). At large interaction strength, the off half-filling spectral density forms a pseudogap near the Fermi level and filling-controlled Mott transition occurs as one approaches the half-filling. As a response property, we finally study the zero temperature optical conductivity and find universal features such as absorption peak position governed by the FL scale and a doping independent crossing point, often dubbed the isosbestic point in experiments.

6 citations

Journal ArticleDOI
TL;DR: Significant changes in the local atomic structure and lattice dynamics were observed by pulsed neutron inelastic scattering measurements on YBa2Cu4O8 both around the superconducting transition temperature and around the spin-gap temperature.
Abstract: Significant changes in the local atomic structure and lattice dynamics were observed by pulsed neutron inelastic scattering measurements on YBa2Cu4O8 both around the superconducting transition temperature and around the spin-gap temperature. These observations and earlier results of numerical calculations on the enhancement of electron-lattice interaction by electron correlation lead to a novel picture of unconventional lattice-induced superconductivity related to antiferroelectric instability.

6 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202334
202271
202165
202064
201968
201871