Delocalizing effect of the Hubbard repulsion for electrons on a two-dimensional disordered lattice

Srinivasan, Bhargavi; Benenti, Giuliano; Shepelyansky, Dima L.

doi:10.1103/physrevb.67.205112

Cited by 36 publications

(50 citation statements)

References 27 publications

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“…[12] confirmed our main finding [16]. While the numerical evidence is mixed concerning the occurrence of a MIT due to interactions, there is a consensus in favor of a Zeeman magnetic field tuned transition [14,15,17,18], as we shall describe in more detail below.…”

supporting

confidence: 81%

“…Later numerical approaches have sometimes [12][13][14][15] led to different conclusions from ours, but they either treat the problem within a Hartree-Fock method, or else use diagonalization methods which deal with considerably smaller numbers of electrons than can be studied in our approach. Very recently, an improved study using the same approach as in Ref.[12] confirmed our main finding [16]. While the numerical evidence is mixed concerning the occurrence of a MIT due to interactions, there is a consensus in favor of a Zeeman magnetic field tuned transition [14,15,17,18], as we shall describe in more detail below.…”

supporting

confidence: 70%

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Interacting Electrons in a Two-Dimensional Disordered Environment: Effect of a Zeeman Magnetic Field

Denteneer

Scalettar

2003

Phys. Rev. Lett.

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The effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the Determinant Quantum Monte Carlo method, the temperature-and magnetic-fielddependent conductivity is calculated, as well as the degree of spin polarization. We find that the Zeeman magnetic field suppresses the metallic behavior present for certain values of interaction-and disorder-strength, and is able to induce a metal-insulator transition at a critical field strength. It is argued that the qualitative features of magnetoconductance in this microscopic model containing both repulsive interactions and disorder are in agreement with experimental findings in two-dimensional electron-and hole-gases in semiconductor structures.A hundred years after the Nobel prize was awarded in 1902 for the discovery of the Zeeman effect and the subsequent explanation by Lorentz, applying a magnetic field continues to be a powerful means to elucidate puzzling phenomena in nature. One of the most recent examples is the interplay of interactions and disorder in electronic systems. This field has witnessed a revival of scientific activity after pioneering experiments in low-density silicon metal-oxide-semiconductor field-effect transistors (MOSFETs) found clear indications of a metal-insulator transition (MIT) in effectively two-dimensional (2D) systems [1]. Until then, electrons in a 2D disordered environment were thought to always form an insulating phase; this mind-set was based on the scaling theory of localization for non-interacting electrons, supplemented by perturbative treatments of weak interactions, as well as studies of the limiting case of very strong interactions. The surprising phenomena were soon confirmed in other semiconductor heterostructures, although the interpretation in terms of a quantum phase transition remains controversial, and a wide variety of experimental and theoretical approaches were unleashed at the problem [2].Among these approaches is the application of magnetic fields. Contrary to the well-known effect of a magnetic field in weak-localization theory to disturb interference phenomena and hence undo localization and insulating behavior, the negative magnetoresistance effect [3], in the Si MOSFETs and similar heterostructures, the magnetic field is found to suppress the metallic behavior and therefore promote insulating behavior [4][5][6]. The effect is present for all orientations of the magnetic field relative to the 2D plane of the electrons. In particular, a Zeeman magnetic field, applied parallel to the 2D plane of electrons and therefore coupling only to the spin, and not the orbital motion of the electrons, has been used extensively. This puts into focus the important role played by the spin degree of freedom of the electron, and its polarization [7][8][9][10].In this Letter, we present a numerical study of a microscopic model for interacting electrons in a disordered environment including the effect of a Zeeman magnetic field. The presen...

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confidence: 81%

supporting

confidence: 70%

Interacting Electrons in a Two-Dimensional Disordered Environment: Effect of a Zeeman Magnetic Field

Denteneer

Scalettar

2003

Phys. Rev. Lett.

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“…79 In this case, for N particles, n i is the difference between the ground-state densities with N + 1 and N particles, a clear operational prescription for finite systems. Using ζ 2 (Ref.…”

Section: A the Inverse Participation Ratiomentioning

confidence: 99%

Interacting fermions in one-dimensional disordered lattices: Exploring localization and transport properties with lattice density-functional theories

et al. 2013

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We investigate the static and dynamical behavior of one-dimensional interacting fermions in disordered Hubbard chains contacted to semi-infinite leads. The chains are described via the repulsive Anderson-Hubbard Hamiltonian, using static and time-dependent lattice density-functional theory. The dynamical behavior of our quantum transport system is studied using an integration scheme available in the literature, which we modify via the recursive Lanczos method to increase its efficiency. To quantify the degree of localization due to disorder and interactions, we adapt the definition of the inverse participation ratio to obtain an indicator which is suitable for quantum transport geometries and can be obtained within density-functional theory. Lattice density-functional theories are reviewed and, for contacted chains, we analyze the merits and limits of the coherent-potential approximation in describing the spectral properties, with interactions included via lattice density-functional theory. Our approach appears to be able to capture complex features due to the competition between disorder and interactions. Specifically, we find a dynamical enhancement of delocalization in the presence of a finite bias and an increase of the steady-state current induced by interparticle interactions. This behavior is corroborated by results for the time-dependent densities and for the inverse participation ratio. Using short isolated chains with interaction and disorder, a brief comparative analysis between time-dependent density-functional theory and exact results is then given, followed by general concluding remarks.

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“…11,12,13,14 Much of the recent progress has been for infinite-dimensional systems 14,15,16,17,18,19,20,21 and the applicability of this work to two and three dimensions is not well established. A recent focus has been the extent to which interactions screen the disorder potential 19,21,22,23 and whether screening may lead to an insulator-metal transition. 12,22,23,24 In particular, some calculations show perfect screening near the Mott transition.…”

Section: Introductionmentioning

confidence: 99%

Dynamical mean field study of the two-dimensional disordered Hubbard model

2008

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We study the paramagnetic Anderson-Hubbard model using an extension of dynamical mean-field theory (DMFT), known as statistical DMFT, that allows us to treat disorder and strong electronic correlations on equal footing. An approximate nonlocal Green's function is found for individual disorder realizations and then configuration-averaged. We apply this method to two-dimensional lattices with up to 1000 sites in the strong disorder limit, where an atomic-limit approximation is made for the self-energy. We investigate the scaling of the inverse participation ratio at quarterand half-filling and find a nonmonotonic dependence of the localization length on the interaction strength. For strong disorder, we do not find evidence for an insulator-metal transition, and the disorder potential becomes unscreened near the Mott transition. Furthermore, strong correlations suppress the Altshuler-Aronov density of states anomaly near half-filling.

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Delocalizing effect of the Hubbard repulsion for electrons on a two-dimensional disordered lattice

Cited by 36 publications

References 27 publications

Interacting Electrons in a Two-Dimensional Disordered Environment: Effect of a Zeeman Magnetic Field

Interacting Electrons in a Two-Dimensional Disordered Environment: Effect of a Zeeman Magnetic Field

Interacting fermions in one-dimensional disordered lattices: Exploring localization and transport properties with lattice density-functional theories

Dynamical mean field study of the two-dimensional disordered Hubbard model

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