Evidence for CuO conducting band splitting in the nodal direction of Bi-2212

TL;DR

This study uses high-resolution ARPES to explicitly resolve bilayer splitting in Bi-2212's nodal direction across various doping levels, showing consistent splitting size and agreement with band structure calculations, indicating no electronic confinement within bilayers.

Contribution

First direct observation of bilayer splitting in Bi-2212's nodal direction across a wide doping range using high-resolution ARPES.

Findings

Bilayer splitting is observed across a wide doping range.

Splitting size does not depend on doping within experimental uncertainty.

Experimental splitting agrees with band structure calculations.

Abstract

Using angle-resolved photoemission spectroscopy with ultimate momentum resolution we have explicitly resolved the bilayer splitting in the nodal direction of Bi-2212. The splitting is observed in a wide doping range and, within the experimental uncertainty, its size does not depend on doping. The value of splitting derived from the experiment is in good agreement with that from band structure calculations which implies the absence of any electronic confinement to single planes within bilayers of Bi-2212. Other consequences of this finding are also discussed.