Planar tunneling spectroscopy of Y1-xPrxBa2Cu3O7 thin films as a function of crystallographic orientation

M. Covington, L. H. Greene

Research output: Contribution to journalArticle

Abstract

We present a systematic study of the charge transport and quasiparticle tunneling properties of Y1-xPrxBa2Cu3O7 thin films. Pr doping increases the resistivity along the copper oxide planes and suppresses the superconducting critical temperature Tc, ultimately inducing a superconductor-insulator transition. The tunneling conductance is reproducible and correlated with the crystallographic film orientation. The crystallographic dependence can be divided into two distinct categories: Tunneling into (001)-oriented (c-axis) films and tunneling into (100)-, (110)-, and (103)-oriented (ab-oriented) films. c-axis tunneling data exhibit a conductance dip at zero bias and a broad temperature-dependent peak over ∼15-40 mV that decreases in magnitude but stays fixed in energy for increasing Pr doping levels, ab-plane tunneling data exhibit a zero-bias x conductance peak and a gaplike feature at an energy that scales roughly linearly with Tc for x=0.0, 0.2, and 0.4. When x=0.5, the resistivity is not linear in temperature and a zero-bias conductance dip is observed. The background conductance that ensures conservation of states in the low-temperature ab-plane data exhibits temperature- and doping-dependent structure over ∼15-40 mV that is very similar to the peak observed in c-axis tunneling. Finally, analysis of the temperature and magnetic field dependence of the zero bias conductance peak indicates that states are conserved to within ∼20%, supporting its interpretation as a feature of a superconducting density of states.

Original languageEnglish (US)
Pages (from-to)12440-12454
Number of pages15
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume62
Issue number18
DOIs
StatePublished - Nov 1 2000

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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