Atomic-scale quasi-particle scattering resonances in Bi2Sr2CaCu2O8+delta
Low-temperature scanning tunneling spectroscopy of the high transition temperature (high-Tc) cuprate Bi2Sr2CaCu2O8+delta reveals the existence of large numbers of identical regions with diameters of about 3 nanometers that have a relatively high density of low-energy quasi-particle states. Their spatial and spectroscopic characteristics are consistent with theories of strong quasi-particle scattering from atomic-scale impurities in a d-wave superconductor. These characteristics include breaking of local particle-hole symmetry, a diameter near twice the superconducting coherence length, and an inverse square dependence of their local density-of-states on distance from the scattering center. In addition to the validation of d-wave quasi-particle scattering theories, these observations identify a source for the anomalously high levels of low-energy quasi-particles in Bi2Sr2CaCu2O8+delta at low temperatures.
Hudson
EW
Department of Physics, University of California, Berkeley, CA, 94720-7300, USA. Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055, USA.
Pan
SH
Gupta
AK
Ng
K
Davis
JC