Bosonic Mode Mixing in the Superconducting State Spectral Function of Bi_2Sr_2CaCu_2O_{8+delta}

TL;DR

This paper investigates the spectral features of Bi_2Sr_2CaCu_2O_{8+delta} below T_c, attributing the observed peak and hump in photoemission spectra to electron-bosonic mode interactions, possibly linked to neutron resonance.

Contribution

It introduces a model explaining spectral features via bosonic mode mixing that appears only below T_c, providing a new interpretation of the superconducting state's spectral function.

Findings

Sharp low-energy peak persists across momentum space

Hump dispersion correlates with normal state dispersion

Features suggest electron-bosonic mode interaction below T_c

Abstract

Photoemission spectra of Bi_2Sr_2CaCu_2O_{8+delta} below T_c show two features near the (pi,0) point of the zone: a sharp peak at low energy and a higher binding energy hump. We find that the sharp peak persists at low energy even as one moves towards (0,0), while the broad hump shows significant dispersion which correlates well with the normal state dispersion. We argue that these features are naturally explained by the mixing of electrons with a bosonic mode which appears only below T_c, and speculate that the latter may be related to the resonance seen in recent neutron data.