Tunable superconducting critical temperature in ballistic hybrid structures with strong spin-orbit coupling

Abstract

We present a theoretical description and numerical simulations of the superconducting transition in hybrid structures including strong spin-orbit interactions. The spin-orbit coupling is taken to be of Rashba type for concreteness, and we allow for an arbitrary magnitude of the spin-orbit strength as well as an arbitrary thickness of the spin-orbit coupled layer. This allows us to make contact with the experimentally relevant case of enhanced interfacial spin-orbit coupling via atomically thin heavy metal layers. We consider both interfacial spin-orbit coupling induced by inversion asymmetry in an S/F-junction, as well as in-plane spin-orbit coupling in the ferromagnetic region of an S/F/S- and an S/F-structure. Both the pair amplitudes, local density of states and critical temperature show dependency on the Rashba strength and, importantly, the orientation of the exchange field. In general, spin-orbit coupling increases the critical temperature of a proximity system where a magnetic field is present, and enhances the superconducting gap in the density of states. We perform a theoretical derivation which explains these results by the appearance of long-ranged singlet correlations. Our results suggest that $T_c$ in ballistic spin-orbit coupled superconducting structures may be tuned by using only a single ferromagnetic layer.

14 pages, 14 figures. Published in PRB

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• Evidence for Triplet Superconductivity in a Superconductor-Ferromagnet Spin Valve
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Cited by in corpus (12)

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• Magnetization reorientation due to the superconducting transition in heavy-metal heterostructures
• Enhanced spin-triplet pairing in magnetic junctions with s-wave superconductors
• Supercurrent in ferromagnetic Josephson junctions with heavy metal interlayers. II. Canted magnetization
• Controlling the Superconducting Transition by Rotation of an Inversion Symmetry-Breaking Axis
• Proximity effect in a ferromagnetic semiconductor with spin-orbit interactions
• Magnetic anisotropy of superconducting transition in S/AF heterostructures with spin-orbit coupling
• Signatures of enhanced spin-triplet superconductivity induced by interfacial properties
• Enhanced controllable triplet proximity effect in superconducting spin-orbit coupled spin valves with modified superconductor/ferromagnet interfaces
• Neel proximity effect in superconductor/antiferromagnet heterostructures
• Upper critical fields in normal metal-superconductor-normal metal trilayers
• Triplet correlations in superconductor/antiferromagnet heterostructures: dependence on type of antiferromagnetic ordering