Impurity induced low-energy resonances in Bi_2Sr_2CaCu_2O_{8+delta}

Abstract

We study sharp low-energy resonance peaks in the local density of states (LDOS) induced by Zn impurities or possible Cu vacancies in superconducting Bi_2Sr_2CaCu_2O_{8+delta}. The measured structure of these near-zero-bias resonances is quantitatively reproduced by an extended impurity potential without invoking internal impurity states or sophisticated tunneling models. The Zn potential extends at least to the nearest-neighbor Cu sites, and the range of order parameter suppression extends at least 8 Åaway from the Zn site. We further show that the local spin susceptibilities near Zn impurities increase rather than decrease with decreasing temperature in the superconducting state due to the sharp increase of LDOS near the Fermi level.

5 pages, 4 figures

References in corpus (1)

• Van Hove features in BSCCO(2212) and effective parameters for Ni impurities inferred from STM spectra

Cited by in corpus (5)

• Scanning tunneling spectroscopy of high-temperature superconductors
• Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates
• Disappearance of zinc impurity resonance in large gap region on Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ probed by scanning tunneling spectroscopy
• Extinction of impurity resonances in large-gap regions of inhomogeneous d-wave superconductors
• Temperature dependence of the impurity-induced resonant state in Zn-doped Bi_2Sr_2CaCu_2O${}_{8+\delta }$ by Scanning Tunneling Spectroscopy