Anomalies in the Fermi surface and band dispersion of quasi-one-dimensional CuO chains in the high-temperature superconductor YBa2Cu4O8

TL;DR

This study uses microprobe ARPES to explore the electronic structure of CuO chains in YBa2Cu4O8, revealing disconnected Fermi surface segments and a kink in band dispersion linked to bosonic modes, advancing understanding of high-Tc superconductivity.

Contribution

It provides the first detailed ARPES analysis of CuO chains, showing Fermi surface segmentation and a dispersion kink similar to CuO2 planes, suggesting a common origin of bosonic modes.

Findings

Fermi surface consists of six disconnected segments.

Presence of a ~40 meV kink in band dispersion.

Kink properties match those in CuO2 planes.

Abstract

We have investigated the electronic states in quasi one dimensional (1D) CuO chains by microprobe Angle Resolved Photoemission Spectroscopy. We find that the quasiparticle Fermi surface consists of six disconnected segments, consistent with recent theoretical calculations that predict the formation of narrow, elongated Fermi surface pockets for coupled CuO chains. In addition, we find a strong renormalization effect with a significant kink structure in the band dispersion. The properties of this latter effect [energy scale (~40 meV), temperature dependence and behavior with Zn-doping] are identical to those of the bosonic mode observed in CuO2 planes of high temperature superconductors, indicating they have a common origin.