A re-examination of the electronic structure of Bi_2Sr_2CaCu_2O_{8+d} and Bi_2Sr_2Cu_1O_{6+d} - An electron-like Fermi Surface and the absence of flat bands at $E_F$

TL;DR

This study re-examines the electronic structure of Bi-based cuprates using refined photoemission techniques, revealing an electron-like Fermi surface and the absence of flat bands at the Fermi level, challenging previous findings.

Contribution

It introduces stricter Fermi surface crossing criteria and varied photon energies, leading to new insights into the Fermi surface topology of Bi-2212 and Bi-2201.

Findings

Identifies an electron-like Fermi surface centered at Gamma.

Finds flat bands at E_F near M are absent.

Results are consistent across doping levels and sample types.

Abstract

We present a re-examination of the electronic structure and Fermi Surface (FS) of Bi-Sr-Ca-Cu-O (BSCCO) as obtained from angle-resolved photoemission experiments. By applying a stricter set of FS crossing criteria as well as by varying the incident photon energy outside the usual range, we have found very different behavior from that previously observed. In particular we have found an electron-like FS centered around the Gamma point, and the flat bands at E_F near the M point of the zone are absent. These results are robust over a large range of dopings and from single to double layer samples.