The magneto-transport study for spin-orbit coupling in CoSi₂/Si heterostructures

Shao-Pin Chiu^1*, Yi-Chun Lin², Chang-Ran Wang¹, Juhn-Jong Lin^1,2

¹Institute of Physics, National Chiao Tung University, Hsinchu, Taiwan
²Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan

* Presenter:Shao-Pin Chiu, email:fluentbb@gmail.com

Cobalt disilicide (CoSi₂) is a non-ferromagnetic material that can be epitaxially grown on silicon substrates with good metallic conductivity and a superconducting phase transition around 1.5 K. Even cobalt and silicon are not heavy elements CoSi₂ exhibits significant spin-orbit (SO) coupling, but the detailed mechanism is not yet clear. With the method of solid-state reaction, we have made a series of epitaxial CoSi₂ films of different thicknesses on either Si(100) or Si(111) substrates. After extracting the SO scattering time from low-temperature positive magnetoresistances with the theory of weak antilocalization effect, we found that the SO scattering rate is enhanced with decreasing film thickness. The underlying reason could be related to the local electric field at interfaces (CoSi₂/Si interface or CoSi₂ top surface) or the strain inside the film. Our experimental result can give useful information for clarifying the mechanism of the SO coupling in the CoSi₂/Si system.

Keywords: Cobalt disilicide, spin-orbit coupling, weak antilocalization effect, superconductivity