Structural origin of apparent Fermi surface pockets in angle-resolved photoemission of Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$

TL;DR

This study reveals that apparent Fermi surface pockets in Bi-based cuprates observed via ARPES are due to structural superstructure replicas, not intrinsic electronic features, challenging previous interpretations of the pseudogap phase.

Contribution

It demonstrates that observed Fermi surface pockets are caused by structural superstructure effects, not intrinsic electronic properties, clarifying the true Fermi surface topology in these materials.

Findings

Apparent Fermi surface pockets are due to superstructure replicas.

ARPES polarization analysis distinguishes structural effects from intrinsic features.

Recent reports of hole pockets are explained by structural origins, not intrinsic electronic structure.

Abstract

We observe apparent hole pockets in the Fermi surfaces of single-layer Bi-based cuprate superconductors from angle-resolved photoemission (ARPES). From detailed low-energy electron diffraction measurements and an analysis of the ARPES polarization-dependence, we show that these pockets are not intrinsic, but arise from multiple overlapping superstructure replicas of the main and shadow bands. We further demonstrate that the hole pockets reported recently from ARPES [Meng et al, Nature 462, 335 (2009)] have a similar structural origin, and are inconsistent with an intrinsic hole pocket associated with the electronic structure of a doped CuO$_2$ plane. The nature of the Fermi surface topology in the enigmatic pseudogap phase therefore remains an open question.