Electron-electron interactions in one- and three-dimensional mesoscopic disordered rings: A perturbative approach

Ramin, M.; Reulet, Bertrand; Bouchiat, H.

doi:10.1103/physrevb.51.5582

Cited by 31 publications

(32 citation statements)

References 20 publications

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“…This critical value of K can be realized for a simple Hubbard model (the maximum K for the Hubbard model is K = 2 68,46 ) whereas the one chain Hubbard model is always localized even for very negative U 46 . In addition the localization length is increased (63) whereas in the one chain case…”

Section: Sc S Sectormentioning

confidence: 98%

Effects of disorder on two strongly correlated coupled chains

1997

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We study the effects of disorder on a system of two coupled chain of strongly correlated fermions (ladder system), using a renormalization group technique. The stability of the phases of the pure system has been investigated as a function of interactions both for fermions with spin and spinless fermions. For spinless fermions the repulsive side is strongly localized whereas the system with attractive interactions is stable with respect to disorder, at variance with the single chain case. For fermions with spins, the repulsive side is also localized, and in particular the d-wave superconducting phase found for the pure system is totally destroyed by an arbitrarily small amount of disorder. On the other hand the attractive side is again remarkably stable with respect to localization. We have also computed the charge stiffness, the localization length and the temperature dependence of the conductivity for the various phases. In the range of parameter where d-wave superconductivity would occur for the pure system the conductivity is found to decrease monotonically with temperature, even at high temperature, and we discuss this surprising result. For a model with one site repulsion and nearest neighbor attraction, the most stable phase is an orbital antiferromagnet . Although this phase has no divergent superconducting fluctuation it can have a divergent conductivity at low temperature. Finally, to make comparison of our results with experimental ladder systems, we treated the interladder coupling in a mean field approximation. We argue based on our results that the superconductivity observed in some of these compounds cannot be a simple stabilization of the d-wave phase found for a pure single ladder. Application of our results to systems such as quantum wires is also discussed. In particular the corrections to conductance in a two channel quantum wire have been obtained as a function of system length, temperature and interactions.

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Section: Sc S Sectormentioning

confidence: 98%

Effects of disorder on two strongly correlated coupled chains

1997

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“…Jv,71.27.+a,73.20.Dx There has been much recent interest in the physics of interacting electrons in disordered systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Part of this attention is motivated by the large amplitudes of persistent currents observed in mesoscopic metallic rings [20,21].…”

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confidence: 99%

Interacting Electrons in Disordered Potentials: Conductance versus Persistent Currents

Berkovits¹,

Avishai²

1996

Phys. Rev. Lett.

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An expression for the conductance of interacting electrons in the diffusive regime as a function of the ensemble averaged persistent current and the compressibility of the system is presented. This expression involves only ground-state properties of the system. The different dependencies of the conductance and persistent current on the electron-electron interaction strength becomes apparent. The conductance and persistent current of a small system of interacting electrons are calculated numerically and their variation with the strength of the interaction is compared. It is found that while the persistent current is enhanced by interactions, the conductance is suppressed.PACS numbers: 71.55. Jv,71.27.+a,73.20.Dx There has been much recent interest in the physics of interacting electrons in disordered systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Part of this attention is motivated by the large amplitudes of persistent currents observed in mesoscopic metallic rings [20,21]. These values are larger by up to two orders of magnitude than theoretical predictions based on the single electron picture using the value of the mean free path as measured by transport experiments. Another motivation has to do with the rich physics contained therein. The metal-insulator transition can be triggered by two different physical mechanisms: electron-electron (e-e) interactions (generally referred to as the Mott-Hubbard transition) and disorder (known as the Anderson transition). Although much effort has been devoted to the investigation of the interplay between the two, the problem of metal-insulator transition in the presence of disorder and interactions is not yet completely settled [22,23].Theoretically, it has been established that due to e-e interactions the amplitude of the persistent current (at zero-temperature) may be enhanced compared to its noninteracting value. The precise nature of this interaction induced modification depends on the model used and on the specific domains in parameter space. For spinless electrons in one-dimensional (1D) continuum models the amplitude can reach its disorder-free value for strong interactions [8]. On the other hand for spinless electrons in 1D lattice models a negligible enhancement of the amplitude occurs and that happens only for weak interactions in the localized regime [9,12,14]. When spin is taken into account, a sizable enhancement of the amplitude is found [17,18]. Large enhancements occur also for 2D and 3D spinless electrons in lattice models for weak and medium ranges of interaction strengths [16,19].Thus one may conclude that it is conceivable that significant enhancement of persistent currents may result in calculations for realistic 3D lattice models which take spin into account. Nevertheless, there still remain several important questions which have not yet been fully answered. The first, and perhaps the most interesting one from a general point of view, is why does e-e interaction play such an important role in the determination of the per...

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“…Both disorder and interelectron interactions are known to play an important role in the magnetic properties of the electron systems. [1][2][3][4] In a quantum ring the repulsive on-site Hubbard interaction gives a paramagnetic contribution to the magnetization, while the nearestneighbor interaction results in a diamagnetic contribution. 4 In a two-dimensional tight-binding model of the electronic system, both the paramagnetic and diamagnetic behaviors have been reported.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4] In a quantum ring the repulsive on-site Hubbard interaction gives a paramagnetic contribution to the magnetization, while the nearestneighbor interaction results in a diamagnetic contribution. 4 In a two-dimensional tight-binding model of the electronic system, both the paramagnetic and diamagnetic behaviors have been reported. [1][2][3] In this context, the DNA molecule is an unique system to study magnetism in nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Influence of correlated electrons on the paramagnetism of DNA

Apalkov

Chakraborty

2008

Phys. Rev. B

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We address the fundamental role of electronic and vibrational interactions on the magnetization of the homogeneous and randomly sequenced DNA. We find several important magnetic properties of DNA: the intrastrand electron-electron interaction enhances magnetization, while the interstrand interaction suppresses it. Renormalization of the hopping integrals due to electron-vibration interactions results in a paramagnetic to diamagnetic transition as a function of temperature. The influence of interelectron interactions is therefore to transform the diamagnetic system into a paramagnetic one while the temperature can reverse that behavior. Being entirely intrinsic, these properties would not be influenced by the environment.

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Electron-electron interactions in one- and three-dimensional mesoscopic disordered rings: A perturbative approach

Cited by 31 publications

References 20 publications

Effects of disorder on two strongly correlated coupled chains

Effects of disorder on two strongly correlated coupled chains

Interacting Electrons in Disordered Potentials: Conductance versus Persistent Currents

Influence of correlated electrons on the paramagnetism of DNA

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