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arXiv · 1805.00047

Superconducting tunneling spectroscopy of spin-orbit coupling and orbital depairing in Nb:SrTiO$_3$

Adrian G. Swartz·Alfred K. C. Cheung·Hyeok Yoon·Zhuoyu Chen·Yasuyuki Hikita·Srinivas Raghu·Harold Y. Hwang
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Abstract

We have examined the intrinsic spin-orbit coupling (SOC) and orbital depairing in thin films of Nb-doped SrTiO$_3$ by superconducting tunneling spectroscopy. The orbital depairing is geometrically suppressed in the two-dimensional limit, enabling a quantitative evaluation of the Fermi level spin-orbit scattering using Maki's theory. The response of the superconducting gap under in-plane magnetic fields demonstrates short spin-orbit scattering times $τ_{so} \leq 1.1$ ps. Analysis of the orbital depairing indicates that the heavy electron band contributes significantly to pairing. These results suggest that the intrinsic spin-orbit scattering time in SrTiO$_3$ is comparable to those associated with Rashba effects in SrTiO$_3$ interfacial conducting layers and can be considered significant in all forms of superconductivity in SrTiO$_3$.

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Adrian G. Swartz, Alfred K. C. Cheung, Hyeok Yoon, Zhuoyu Chen, Yasuyuki Hikita, Srinivas Raghu, Harold Y. Hwang. 2018-04-30. Superconducting tunneling spectroscopy of spin-orbit coupling and orbital depairing in Nb:SrTiO$_3$. https://doi.org/10.1103/physrevlett.121.167003

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