Tuning interfacial two-component superconductivity in CoSi 2 /TiSi 2 heterojunctions via TiSi 2 diffusivity

• Published in: Nanoscale Vol. 15; no. 20; pp. 9179 - 9186
• Main Authors: Chiu, Shao-Pin, Mishra, Vivek, Li, Yu, Zhang, Fu-Chun, Kirchner, Stefan, Lin, Juhn-Jong
• Format: Journal Article
• Language: English
• Published: England 25.05.2023
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/D2NR05864B

We report the observation of enhanced interfacial two-component superconductivity possessing a dominant triplet component in nonmagnetic CoSi /TiSi superconductor/normal-metal planar heterojunctions. This is accomplished through the detection of odd-frequency spin-triplet even-parity Cooper pairs in the diffusive normal-metal component of T-shaped proximity junctions. We show that by modifying the diffusivity of the normal-metal part, the transition temperature enhancement can be tuned by a factor of up to 2.3 while the upper critical field increases by up to a factor of 20. Our data suggest that the C49 phase of TiSi , which is stabilized in confined geometries, underlies this enhancement. These findings are addressed a Ginzburg-Landau model and the quasi-classical theory. We also relate our findings to the enigmatic 3-K phase reported in Sr RuO .