Enhanced two-component superconductivity in CoSi2/TiSi2 heterojunctions

TL;DR

This study demonstrates enhanced two-component superconductivity in CoSi2/TiSi2 heterojunctions, with increased transition temperature and critical field, driven by interface symmetry reduction and odd-frequency triplet pairing.

Contribution

It reveals the enhancement of superconductivity and the presence of odd-frequency triplet pairs in CoSi2/TiSi2 heterojunctions, highlighting the role of interface effects and diffusion.

Findings

Superconducting transition temperature doubled in heterojunctions.

Critical magnetic field increased by a factor of 20.

Pronounced zero-bias conductance peaks indicating triplet pairing.

Abstract

We report enhanced two-component superconductivity in (CoSi2/Si)/TiSi2 superconductor/normal-metal (S/N) heterojunctions. An enhanced superconducting transition temperature about twice that of CoSi2 and an upper critical field about 20 times bigger than that of epitaxial CoSi2/Si films were found. The tunneling spectra of three-terminal S/N junctions show pronounced zero-bias conductance peaks (ZBCPs) that signify penetration of odd-frequency, spin-triplet and even-parity Cooper pairs in TiSi2 from triplet dominant pairing in CoSi2/Si driven by symmetry reduction at the CoSi2/Si interface. Both the enhancement of the superconducting transition temperature and the ZBCPs are found to be more pronounced if TiSi2 is made more diffusive.