Superfluid-insulator transition and the BEC-BCS crossover in the Rashba moat band

Allami, Hassan; Starykh, Oleg A.; Pesin, D. A.

doi:10.1103/physrevb.99.104505

Cited by 3 publications

(3 citation statements)

References 29 publications

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“…2. Twodimensional gated layers a ract now a great deal of a ention, because they represent a system with a highly tunable Rashba SOI [48,58]. Most importantly, at low distances between the electrons, where the electron pairs are formed, the e-e interaction and hence the in-plane electric eld that gives the leading contribution to PSOI are only weakly screened similar to the Rytova-Keldysh potential.…”

Section: D Gated Layersmentioning

confidence: 99%

Pair spin–orbit interaction in low-dimensional electron systems

Gindikin

Sablikov

2020

Eur. Phys. J. Spec. Top.

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The pair spin-orbit interaction (PSOI) is the spin-orbit component of the electron-electron interaction that originates from the Coulomb fields of the electrons. This relativistic component, which has been commonly assumed small in the low-energy approximation, appears large and very significant in materials with the strong SOI. The PSOI, being determined by the spins and momenta of electrons, has highly unusual properties among which of most interest is the mutual attraction of the electrons in certain spin configurations. We review the nature of the PSOI in solids and its manifestations in low-dimensional systems that have been studied to date. The specific results depend on the configuration of the Coulomb fields in a particular structure. The main actual structures are considered: one-dimensional quantum wires and two-dimensional layers, both suspended and placed in various dielectric media, as well as in the presence of a metallic gate. We discuss the possible types of the two-electron bound states, the conditions of their formation, their spectra together with the spin and orbital structure. In a many-particle system, the PSOI breaks the spin-charge separation as a result of which spin and charge degrees of freedom are mixed in the collective excitations.At sufficiently strong PSOI, one of the collective modes softens. This signals of the instability, which eventually leads to the reconstruction of the homogeneous state of the system. arXiv:1905.06340v2 [cond-mat.str-el] 8 Jul 2019 Pair spin-orbit interaction in solidsElectrons in solids form a fruitful ground to raise many ideas born in relativistic quantum theory and to give life to plenty of unexpected phenomena arising from the realization of electron states and band spectra that only recently appeared truly exotic. is became possible largely due to the discovery of new materials and technological advances in nanostructures.Just recall the discovery of graphene [14] and carbon nanotubes [15], topological insulators [16][17][18], Weyl and Dirac semi-metals [19], 2D transition metal dichalcogenides [20], and many more. e wide variety of non-trivial electronic states and spectra is due to the presence of the crystal. Electron motion in the crystal potential is generally speaking described by the relativistic Dirac equation [21], but in practice a quasi-relativistic approximation based on a small ratio /c of the electron velocity to the speed of light is su cient to describe the electronic spectrum of any material. Such an approximation is successful, in particular, in describing the behavior of electron spins, which has opened a whole new land of spin phenomena in solids [22].

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Section: D Gated Layersmentioning

confidence: 99%

Pair spin–orbit interaction in low-dimensional electron systems

Gindikin

Sablikov

2020

Eur. Phys. J. Spec. Top.

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“…The realization of the three-dimensional Rashba-like spin splitting [15] in quantum materials and heterostructures potentially unfolds numerous promising applications. Following the first theoretical study of superconductivity [16] with spin-orbit band splitting in a 2D metallic layer or at the surface of doped WOx oxides, several theoretical works have studied the emergence of superconductivity in the presence of spin-orbit coupling in a 2D metallic layer [17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…The theoretical studies of superconductivity coexisting with spin-orbit coupling have been limited to a 2D superconducting layer and to a single band metal [16][17][18][19][20][21][22][23], while it is not known how superconductivity will arise in a 3D Rashba system. Moreover, previous theoretical investigations have considered single-gap superconductors while, in multi-band 3D superconductors, multiple-gap super-conductivity, in the clean limit, need to be considered in the presence of band spin splitting due to spin-orbit coupling.…”

Section: Introductionmentioning

confidence: 99%

Multigaps superconductivity at unconventional Lifshitz transition in a 3D Rashba heterostructure at atomic limit

Mazziotti,

Valletta,

Raimondi

et al. 2020

Preprint

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It is well known that the critical temperature of multi-gap superconducting 3D heterostructures at atomic limit (HAL) made of a superlattice of atomic layers with an electron spectrum made of several quantum subbands can be amplified by a shape resonance driven by the contact exchange interaction between different gaps. The TC amplification is achieved tuning the Fermi level near the singular nodal point at a Lifshitz transition for opening a neck. Recently high interest has been addressed to the breaking of inversion symmetry which leads to a linear-in-momentum spin-orbit induced spin splitting, universally referred to as Rashba spin-orbit coupling (RSOC) also in 3D layered metals. However the physics of multi-gap superconductivity near unconventional Lifshitz transitions in 3D HAL with RSOC, being in a non-BCS regime, is not known. The key result of this work getting the superconducting gaps by Bogoliubov theory and the 3D electron wave functions by solution of the Dirac equation is the feasibility of tuning multi-gap superconductivity by suitably matching the spin-orbit length with the 3D superlattice period. It is found that the presence of the RSOC amplifies both the k dependent anisotropic gap function and the critical temperature when the Fermi energy is tuned near the circular nodal line. Our results suggest a method to effectively vary the effect of RSOC on macroscopic superconductor condensates via the tuning of the superlattice modulation parameter in a way potentially relevant for spintronics functionalities in several existing experimental platforms and tunable materials needed for quantum devices for quantum computing.

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