Electron correlations due to pair spin–orbit interaction in 2D electron systems

Gindikin, Yasha; Sablikov, V. A.

doi:10.1016/j.physe.2022.115328

Cited by 7 publications

(2 citation statements)

References 35 publications

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“…The results show, however, that suppressing ferroelectricity, i.e., driving the films closer to a putative quantum critical point, in this case via Eu alloying, does not promote superconductivity, contrary to the suggestions of some of the theoretical proposals. There are very few theories that directly connect superconductivity to spin-orbit coupling [72,73], although there are recent suggestions of a more indirect link via a modification of the phonon coupling [8]. We hope that the results motivate further theoretical studies in the role of static polar order in the superconductivity of SrTiO3.…”

Section: Discussionmentioning

confidence: 77%

Ferroelectricity and superconductivity in strained EuxSr1−xTiO3 films

et al. 2023

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The superconducting transition of SrTiO3 can be influenced by tuning its ferroelectric transition, but the underlying reasons remain poorly understood. Here, we investigate compressively strained, Sm-doped films of EuxSr1-xTiO3 that were grown by molecular beam epitaxy to determine the effect of alloying with Eu on both superconductivity and ferroelectricity, both of which are present in strained SrTiO3 films. Remarkably, superconductivity survives up to x = 0.14. Films at the lowest alloy concentration studied here, x = 0.09, exhibit no suppression of their superconducting transition temperature, but a strong reduction of the upper critical field (Hc2), compared to non-alloyed, strained SrTiO3 films. In addition, these films lack the sharp ferroelectric transition that appears in films without Eu in second harmonic generation measurements. We postulate that Eu-alloying causes a crossover from a globally ordered ferroelectric state to one with only short-range polar order. We discuss the connection between the loss of global polar order and the change in the superconducting properties.

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Section: Discussionmentioning

confidence: 77%

Ferroelectricity and superconductivity in strained EuxSr1−xTiO3 films

et al. 2023

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“…We base our study on the Bernevig-Hughes-Zhang (BHZ) model [24], which is well established to describe many quasi-2D systems in both topological and trivial phases. However, in this model, Rashba SOI is due to the 𝑠𝑝 3 band hybridization mechanism, which as we found results in a PSOI not strong enough to reliably overcome the Coulomb interaction [16,25]. Nonetheless, the situation is signi cantly improved in the presence of the SOI produced by the electric eld of the gate, which makes it easier to achieve this condition.…”

Section: Introductionmentioning

confidence: 67%

Electron pairs bound by the spin-orbit interaction in 2D gated Rashba materials with two-band spectrum

Gindikin¹,

Rozhansky²,

Sablikov³

2022

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We show that the bound electron pairs (BEPs) emerge in two-dimensional gated Rashba materials owing to the interplay of the pair spin-orbit interaction, produced by the Coulomb elds of interacting electrons, and the peculiarities of the band structure giving rise to a negative reduced mass of the interacting electrons. Our consideration is based on the four-band Bernevig-Hughes-Zhang model with the Rashba spin-orbit interaction created by the charges on the gate. The binding energy of the BEP varies with the gate voltage in a wide range across the entire width of the two-particle energy gap. Although the spin-orbit interaction destroys the spin quantization, the BEPs have a magnetic moment, which is created mainly by the orbital motion of the electrons and tuned by the gate voltage.

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