Impurity States and Interlayer Tunneling in High Temperature Superconductors

I. Martin; A. V. Balatsky; J. Zaanen

doi:10.1103/PhysRevLett.88.097003

Impurity States and Interlayer Tunneling in High Temperature Superconductors

I. Martin, A. V. Balatsky, and J. Zaanen

Phys. Rev. Lett. 88, 097003 – Published 15 February 2002

Abstract

We argue that the scanning tunneling microscope (STM) images of resonant states generated by doping Zn or Ni impurities into Cu-O planes of BSCCO are the result of quantum interference of the impurity signal coming from several distinct paths. The impurity image seen on the surface is greatly affected by interlayer tunneling matrix elements. We find that the optimal tunneling path between the STM tip and the metal (Cu, Zn, or Ni) $d_{x^{2} {- y}^{2}}$ orbitals in the Cu-O plane involves intermediate excited states. This tunneling path leads to the fourfold nonlocal filter of the impurity state in Cu-O plane that explains the experimental impurity spectra. Applications of the tunneling filter to the Cu vacancy defects and “direct” tunneling into Cu-O planes are also discussed.

Received 22 December 2000

DOI:https://doi.org/10.1103/PhysRevLett.88.097003

Authors & Affiliations

I. Martin¹, A. V. Balatsky¹, and J. Zaanen²

¹Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
²Leiden Institute of Physics, Leiden University, 2333CA Leiden, The Netherlands