Theory of the proximity effect in two-dimensional unconventional superconductors with Rashba spin-orbit interaction

Abstract

We study the anomalous proximity effect in diffusive normal metal (DN)/unconventional superconductor junctions, where the local density of states (LDOS) in the DN has a zero-energy peak due to the penetration of the odd-frequency spin-triplet s-wave pairing. In this study, we consider a two-dimensional unconventional superconductor on the substrate in the presence of a Rashba spinorbit coupling (RSOC) λ, where the Rashba vector is parallel to the z-direction. The anomalous proximity effect, originally predicted in spin-triplet p-wave superconductor junctions, is sensitive to the RSOC. It disappears with the increase of λ. On the other hand, the anomalous proximity effect can be switched on by the large λ values in the spin-singlet dxy-wave superconductor junctions. The resulting zero-energy LDOS and the magnitude of the odd-frequency spin-triplet s-wave pair amplitude increase with the increase of λ.

Effects of spin orbit coupling in superconducting proximity devices -- application to $\mathrm{CoSi_2 / TiSi_2}$ heterostructures

“…It is known that SOC induced pairing does not break the time reversal symmetry 23 , and the presence of the SOC also leads to mixing of the triplet and the singlet components. In the context of noncentrosymmetric superconductors, the tunneling conductance for SN junctions has been studied in systems with SOC [24][25][26][27][28] . However, the effect of the SOC and the conductance for a mixed parity supercon- ductor in a T-junction device is not known.…”

Bulk odd-frequency pairing in the superconducting Su-Schrieffer-Heeger model

“…Odd-frequency (odd-ω) pairing can emerge as a bulk or induced phenomena and it has been shown that the main ingredient in both cases relies on breaking the system symmetries [2][3][4][5]. For instance, it has been shown that odd-ω correlations can be induced in normal-superconductor junctions [3,[5][6][7][8][9][10][11][12][13][14], where their emergence occurs because the spatial parity of Cooper pairs is broken at the junction interface. Moreover, under the presence of a spin field in such junctions, e.g., from a magnetic field or spin-orbit coupling, spins get mixed, which then gives rise to even more exotic spin-triplet odd-ω correlations [2][3][4][5].…”

Bulk odd-frequency pairing in the superconducting Su-Schrieffer-Heeger model

“…[1][2][3][4][5] Odd-frequency (odd-ω) pairing can emerge as a bulk or induced phenomena and it has been shown that the main ingredient in both cases relies on breaking the system symmetries. [2][3][4][5] For instance, it has been shown that odd-ω correlations can be induced in normal-superconductor junctions, 3,[5][6][7][8][9][10][11][12][13][14] where their emergence occurs because the spatial parity of Cooper pairs is broken at the junction interface. Moreover, under the presence of a spin field in such junctions, e.g.…”