Experimental proof of a structural origin for the shadow Fermi surface in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$

TL;DR

This study demonstrates that the shadow Fermi surface in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ originates from structural orthorhombic distortions, resolving a long-standing debate in the material's electronic structure.

Contribution

The paper provides experimental and theoretical evidence linking the shadow Fermi surface to structural distortions, a novel insight in high-temperature superconductor research.

Findings

Shadow Fermi surface has a structural origin due to orthorhombic distortions.

Structural distortions are present in both surface and bulk of the material.

The results resolve a long-standing issue in the fermiology of Bi2212.

Abstract

By combining surprising new results from a full polarization analysis of nodal angle-resolved photoemission data from pristine and modulation-free Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ with structural information from LEED and {\it ab initio} one-step photoemission simulations, we prove that the shadow Fermi surface in these systems has structural origin, being due to orthorhombic distortions from tetragonal symmetry present in both surface and bulk. Consequently, one of the longest standing open issues in the fermiology of these widely studied systems finally meets its resolution.