Possible Mechanisms of Electronic Phase Separation in Oxide Interfaces

Bovenzi, N.; Finocchiaro, F.; Scopigno, Niccolò; Bucheli, D.; Caprara, S.; Seibold, G.

doi:10.1007/s10948-014-2903-7

Cited by 9 publications

(21 citation statements)

References 25 publications

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“…(1) can be written in terms of currents, and the same kind of currents here studied could be the one seen in Ref. 56 in the presence of impurities. That is, the impurities provide the breaking of translational symmetry that appear in our case due to the open boundaries of strip geometry.…”

Section: Noninteracting Case a Rashba Helical Currentsmentioning

confidence: 82%

Helical currents in metallic Rashba strips

Hamad¹,

Gazza²,

Riera³

2016

Phys. Rev. B

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We study the texture of helical currents in metallic planar strips in the presence of Rashba spinorbit coupling (RSOC) on the lattice at zero temperature. In the noninteracting case, and in the absence of external electromagnetic sources, we determine by exact numerical diagonalization of the single-particle Hamiltonian, the distribution across the strip section of these Rashba helical currents (RHC) as well as their sign oscillation, as a function of the RSOC strength, strip width, electron filling, and strip boundary conditions. Then, we study the effects of charge currents introduced into the system by an Aharonov-Bohm flux for the case of rings or by a voltage bias in the case of open strips. The former setup is studied by variational Monte Carlo, and the later, by the time-dependent density-matrix-renormalization group technique. Particularly for strips formed by two, three and four coupled chains, we show how these RHC vary in the presence of such induced charge current, and how their differences between spin-up and spin-down electron currents on each chain, help to explain the distribution across the strip of charge currents, both of the spin conserving and the spin flipping types. We also predict the appearance of polarized charge currents on each chain. Finally, we show that these Rashba helical currents and their derived features remain in the presence of an on-site Hubbard repulsion as long as the system remains metallic, at quarter filling, and even at half-filling where a Mott-Hubbard metal-insulator transition occurs for large Hubbard repulsion.

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Section: Noninteracting Case a Rashba Helical Currentsmentioning

confidence: 82%

Helical currents in metallic Rashba strips

Hamad¹,

Gazza²,

Riera³

2016

Phys. Rev. B

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“…33,34 Of course, the total current along the strip is zero. In the following we will compute RHCs, defined by the spin-up current along x, J ↑ , on each chain of closed strips of width W .…”

Section: Rashba Helical Currentsmentioning

confidence: 99%

Longitudinal optical and spin Hall conductivities of Rashba conducting strips coupled to ferromagnetic and antiferromagnetic layers

Riera

2017

Phys. Rev. B

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A system composed of a conducting planar strip with Rashba spin-orbit coupling (RSOC), magnetically coupled to a layer of localized magnetic moments, at equilibrium, is studied within a microscopic Hamiltonian with numerical techniques at zero temperature in the clean limit. In particular, transport properties for the cases of ferromagnetic (FM) and antiferromagnetic (AFM) coupled layers are computed in linear response on strips of varying width. Some behaviors observed for these properties are consistent with the ones observed for the corresponding Rashba helical currents. The case of uncoupled Rashba strips is also studied for comparison. In the case of Rashba strips coupled to an AFM localized order, results for the longitudinal dc conductivity, for small strip widths, suggest the proximity to a metal-insulator transition. More interesting, in the proximity of this transition, and in general at intermediate values of the RSOC, it is observed a large spin-Hall conductivity that is two orders of magnitude larger than the one for the FM order for the same values of the RSOC and strip widths. There are clearly two different regimes for small and for large RSOC, which is also present in the behavior of Rashba helical currents. Different contributions to the optical and the spin-Hall conductivities, according to a new classification of inter-or intra-band origin proposed for planar strips in the clean limit, or coming from the hopping or spin-orbit terms of the Hamiltonian, are examined. Finally, the effects of different orientation of the coupled magnetic moments will be also studied.

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“…In a strict sense, it is induced in a chemically homogeneous solid when competing internal or mutual interactions between the charge, spin, orbit, and lattice degrees of freedom happen to depend strongly on electron density. Examples for such interactions include the superconducting pairing interaction, magnetic exchange or Rashba spin-orbit coupling [36,37].…”

Section: Control Of Separate Electronic Phasesmentioning

confidence: 99%

“…Stimulated by the experimental observations theoretical work related to electronic phase separation at oxide interfaces was performed by Nanda and Satpathy [51], Caprara et al [52], Pavlenko et al [53], Bucheli et al [54], Bovenzi et al [37], Seibold et al [55], and Scopigno et al [56]. These studies draw up scenarios which are specific to oxide surfaces and interfaces to varying degrees and comprise mechanisms involving electron-phonon coupling [51], Rashba spin-orbit coupling [37,52,54,55], oxygen vacancies [53], the superconducting pairing interaction [37], and the electrostatic confinement potential at the interface [37,56].…”

Section: Control Of Separate Electronic Phasesmentioning

confidence: 99%

“…These studies draw up scenarios which are specific to oxide surfaces and interfaces to varying degrees and comprise mechanisms involving electron-phonon coupling [51], Rashba spin-orbit coupling [37,52,54,55], oxygen vacancies [53], the superconducting pairing interaction [37], and the electrostatic confinement potential at the interface [37,56].…”

Section: Control Of Separate Electronic Phasesmentioning

confidence: 99%

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Influence of oxygen vacancies on two-dimensional electron systems at SrTiO3-based interfaces and surfaces

Sing

Jeschke

Lechermann

et al. 2017

Eur. Phys. J. Spec. Top.

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Abstract. The insulator SrTiO 3 can host high-mobility twodimensional electron systems on its surfaces and at interfaces with other oxides. While for the bare surface a two-dimensional electron system can only be induced by oxygen vacancies, it is believed that the metallicity of heterostructure interfaces as in LaAlO 3/SrTiO3 is caused by other mechanisms related to the polar discontinuity at the interface. Based on calculations using density functional and dynamical mean-field theory as well as on experimental results using photoemission spectroscopy we elucidate the role of oxygen vacancies, thereby highlighting their importance for the electronic and magnetic properties of the systems under study.

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Possible Mechanisms of Electronic Phase Separation in Oxide Interfaces

Cited by 9 publications

References 25 publications

Helical currents in metallic Rashba strips

Helical currents in metallic Rashba strips

Longitudinal optical and spin Hall conductivities of Rashba conducting strips coupled to ferromagnetic and antiferromagnetic layers

Influence of oxygen vacancies on two-dimensional electron systems at SrTiO3-based interfaces and surfaces

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