Observation of triplet superconductivity in CoSi₂/TiSi₂ heterostructures
Shao-Pin Chiu1*, C. C. Tsuei2,3, Sheng-Shiuan Yeh1,4, Fu-Chun Zhang5, Stefan Kirchner6,7, Juhn-Jong Lin1,8
1Institute of Physics and Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
2Thomas J. Watson Research Center, IBM, Yorktown Heights, NY 10598, USA
3Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan
4International College of Semiconductor Technology, National Yang Ming Chiao Tung Universty, Hsinchu 30010, Taiwan
5Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
6Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China
7Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310027, China
8Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
* Presenter:Shao-Pin Chiu, email:spchiu@nycu.edu.tw
Spin-triplet superconductivity is of considerable interest to fundamental research and quantum technological applications. Here we report our observation of triplet pairing in nonmagnetic CoSi₂/TiSi₂ heterostructures on silicon. CoSi₂ is a superconductor (S) with a sharp superconducting transition at Tc ≈ 1.5 K, while TiSi₂ is a normal metal (N). We investigate conductance spectra of both CoSi₂/TiSi₂ S/N junctions and T-shaped CoSi₂/TiSi₂ superconducting proximity structures. Below Tc, we observe (i) a narrow zero-bias conductance peak on top of a broad hump, accompanied by two symmetric side dips in the S/N junctions, (ii) a narrow zero-bias conductance peak in T-shaped structures, and (iii) hysteresis in the S/N junction magnetoresistance. These three independent and complementary observations point to chiral p-wave pairing in CoSi₂/TiSi₂ heterostructures. The excellent fabrication compatibility of CoSi₂ and TiSi₂ with current silicon-based integrated-circuit technology suggests their potential use in scalable quantum-computing devices.

Keywords: triplet superconductivity, CoSi₂/TiSi₂ heterostructure, conductance spectra, S/N junction, T-shaped structure