Surface investigation of Ca$_{1-x}$Pr$_{x}$Fe$_{2}$As$_{2}$ by scanning tunneling microscopy

ORAL

Abstract

Rare-earth-doped CaFe$_{2}$As$_{2}$ exhibits small volume-fraction superconductivity up to 49 K of unknown origin [1,2]. We use scanning tunneling microscopy to locally probe possible sources of this phase in Ca$_{1-x}$Pr$_{x}$Fe$_{2}$As$_{2}$. We encounter three kinds of surface morphologies and infer their chemical identities with local work function measurements. We also image Pr$^{3+}$ dopants as positive-energy resonances in tunneling conductance and examine their relationship with an observed inhomogeneous spectral gap. [1] B. Lv, L. Denga, M. Goocha, F. Weia, Y. Suna, J. K. Meena, Y.-Y. Xuea, B. Lorenza, and C.-W. Chu, Proc. Nat. Acad. Sci. 108, 15705 (2011). [2] S. R. Saha, N. P. Butch, T. Drye, J. Magill, S. Ziemak, K. Kirshenbaum, P. Y. Zavalij, J. W. Lynn, and J. Paglione, Phys. Rev. B 85, 024525 (2012)

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Authors

  • Dennis Huang

    • Harvard University

  • Ilija Zeljkovic

    • Harvard University

  • Can-Li Song

    • Harvard University
    • Department of Physics, Harvard University, Cambridge, MA 02138, USA

  • Bing Lv

    • Texas Center for Superconductivity, University of Houston
    • University of Houston
    • Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204-5002

  • Paul Chu

    • Texas Center for Superconductivity, University of Houston
    • University of Houston
    • Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204-5002
    • Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, TX 77204-5002 \& Lawrence Berkeley National Laboratory

  • Jennifer Hoffman

    • Harvard University