Dislocations and the enhancement of superconductivity in odd-parity superconductor Sr$_2$RuO$_4$

ORAL

Abstract

We investigated the 3-K phase of spin-triplet, odd-parity superconductor Sr$_2$RuO$_4$, which was usually referred to the eutectic phase of Ru and Sr$_2$RuO$_4$ featuring Ru islands embedded in single crystalline Sr$_2$RuO$_4$. Using single-crystal flakes of Sr$_2$RuO$_4$ of mesoscopic size free of Ru, we observed an enhancement of superconducting transition temperature ($T_c$) up to about twice of that of the bulk when lattice dislocations were found in the samples, a surprising result given the well known sensitivity of superconductivity in Sr$_2$RuO$_4$ to disorder. We formulated a phenomenological theory taking into account the crystalline as well as the pairing symmetry of Sr$_2$RuO$_4$ and showed that the enhanced $T_c$ can be attributed to symmetry reduction in superconductors with a two-component order parameter. We found that our experimental results are consistent with the theoretical predictions.

*The work is supported by DOE under Grant No. DE-FG02-04ER4615

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Authors

  • Yiqun Ying

    • Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

  • Neal Staley

    • Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

  • Xinxin Cai

    • Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

  • Ying Liu

    • Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

  • Yan Xin

    • National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA

  • Kai Sun

    • Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA

  • David Fobes

    • Department of Physics, Tulane University, New Orleans, Louisiana 70118, USA

  • Tijiang Liu

    • Department of Physics, Tulane University, New Orleans, Louisiana 70118, USA

  • Zhiqiang Mao

    • Department of Physics, Tulane University, New Orleans, Louisiana 70118, USA