Anomalous proximity effect for d-wave superconductor with Rashba spin-orbit interaction*

In the usual case, the local density of states (LDOS) in a diffusive normal metal (DN) for DN-superconductor junction is almost constant as a function of energy due to scattering in the DN. On the other hand, for DN-p-wave superconductor junction, zero energy peak for the LDOS in the DN is expected due to penetration of odd-frequency spin-triplet s-wave Cooper pair amplitude, and this phenomena is called an anomalous proximity effect. The anomalous proximity effect is theoretically predicted but has not been observed yet because of the lack of candidate materials. We study a DN-d-wave superconductor with Rashba spin-orbit interaction junction[1]. In the absence of Rashba spin-orbit interaction, the anomalous proximity effect does not occur. Rashba spin-orbit interaction generates odd-frequency spin-triplet s-wave pairing at the interface which is robust against impurity scattering and we found this system shows the anomalous proximity effect.
[1]PRB 99, 184501 (2019).