Interface effects on the shot noise in normal metal- d-wave superconductor Junctions

TL;DR

This paper investigates how interface orientation and bound states in normal metal-d-wave superconductor junctions affect shot noise, revealing that zero-energy states suppress noise, while time-reversal symmetry breaking enhances it.

Contribution

It provides a detailed analysis of shot noise influenced by Andreev bound states and interface effects in d-wave superconductor junctions, including the impact of subdominant s-wave components.

Findings

Zero-energy Andreev bound states suppress shot noise at zero voltage.

Presence of subdominant s-wave component increases noise power to current ratio to 4e.

Interface orientation significantly affects the shot noise behavior.

Abstract

The current fluctuation in normal metal / d-wave superconductor junctions are studied for various orientation of the crystal by taking account of the spatial variation of the pair potentials. Not only the zero-energy Andreev bound states (ZES) but also the non-zero energy Andreev bound states influence on the properties of differential shot noise. At the tunneling limit, the noise power to current ratio at zero voltage becomes 0, once the ZES are formed at the interface. Under the presence of a subdominant s-wave component at the interface which breaks time-reversal symmetry, the ratio becomes 4e