Imaging Quasiparticle Interference in Bi2Sr2CaCu2O8+d

TL;DR

This paper uses Fourier analysis of scanning tunneling spectroscopy images to study quasiparticle interference in Bi2Sr2CaCu2O8+d, revealing how elastic scattering explains conductance modulations and introducing a new momentum-resolved technique.

Contribution

It demonstrates a novel application of Fourier analysis to tunneling data, linking quasiparticle interference to conductance modulations in high-Tc cuprates.

Findings

Quasiparticle interference explains incommensurate conductance modulations.

Energy-dependent wavevector dispersions match photoemission data.

Introduces a new momentum-resolved tunneling spectroscopy method.

Abstract

Scanning tunneling spectroscopy of the high-Tc superconductor Bi2Sr2CaCu2O8+d reveals weak, incommensurate, spatial modulations in the tunneling conductance. Images of these energy-dependent modulations are Fourier analyzed to yield the dispersion of their wavevectors. Comparison of the dispersions with photoemission spectroscopy data indicates that quasiparticle interference, due to elastic scattering between characteristic regions of momentum-space, provides a consistent explanation for the conductance modulations, without appeal to another order parameter. These results refocus attention on quasiparticle scattering processes as potential explanations for other incommensurate phenomena in the cuprates. The momentum-resolved tunneling spectroscopy demonstrated here also provides a new technique with which to study quasiparticles in correlated materials.