Anomalous dispersion in the autocorrelation of ARPES data of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$

TL;DR

This study reveals that autocorrelation peaks in ARPES data of Bi2212 exhibit dispersive behavior below the superconducting gap and anomalous dispersion above it, indicating electron interactions with collective excitations, with contrasting behavior in the pseudogap phase.

Contribution

The paper demonstrates the energy-dependent dispersion and anomalous behavior of autocorrelation peaks in ARPES data of Bi2212, linking it to electron interactions and collective excitations.

Findings

Dispersive autocorrelation peaks below the superconducting gap.

Anomalous dispersion of peaks at energies above the gap.

Dispersionless behavior observed in the pseudogap phase.

Abstract

We find that peaks in the autocorrelation of angle resolved photoemission spectroscopy data of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ in the superconducting state show dispersive behavior for binding energies smaller than the maximum superconducting energy gap. For higher energies, though, a striking anomalous dispersion is observed that is a consequence of the interaction of the electrons with collective excitations. In contrast, in the pseudogap phase, we only observe dispersionless behavior for the autocorrelation peaks. The implications of our findings in regards to Fourier transformed scanning tunneling spectroscopy data are discussed.