Search for Higher Tc Superconductors via Interface Mechanism and High Pressure

ORAL

Abstract

Since the discovery of superconductivity in 1911, researchers have continued the search for superconductors with higher transition temperatures (Tc). Many strides have been made with the increase of the Tc, as can been seen from the evolution of record Tc over time. We believe a holistic multidisciplinary enlightened empirical approach can be most fruitful. Two paths have been adopted to raise Tc: to realize novel mechanism inspired by the theoretical models and to discover new compounds guided by experience and insight empirically. Over the last few years, we discovered nonbulk superconductivity in rare-earth doped CaFe2As2 (Ca122) with an onset Tc of 49 K, which is higher than the Tc of any known compounds formed of the constituent elements at ambient or under high pressures. We successfully induced superconductivity with a Tc of 25 K in the mixed phase region of two non-superconducting phases in undoped Ca122. We also observed a universal increase of Tc under high pressure in BSCCO. Our systematical studies in R-doped Ca122 and undoped Ca122 both suggest that the observations may be attributed to an interface-induced Tc and our investigation on BSCCO reveals that ultra-high pressure may help to break away from the predictions by the rigid band model and reach even higher Tcs.

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Presenters

  • Liangzi Deng

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204, USA, University of Houston

Authors

  • Liangzi Deng

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204, USA, University of Houston

  • Hanming Yuan

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, University of Houston

  • Shuyuan Huyan

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, University of Houston

  • Luke Kelly

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA

  • Rabin Dahal

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA

  • Samira Daneshmandi

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, University of Houston

  • Moein Adnani

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA

  • Zheng Wu

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204, USA, University of Houston

  • Melissa Gooch

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204, USA

  • Yanfeng Lyu

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, University of Houston

  • Hungcheng Wu

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, Department of Physics, National Sun Yat-sen University, Kaohsiung, 8042

  • C. W. Paul Chu

    Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204, USA, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA, Department of Physics and Texas Center for Superconductivity, University of Houston, University of Houston, University of Houston, Lawrence Berkeley National Laboratory