Crossover from coherent to incoherent electronic excitations in the normal state of Bi2Sr2CaCu2O8

TL;DR

This study identifies a crossover in Bi2Sr2CaCu2O8+delta from a coherent metallic state with well-defined spectral features to an incoherent metallic state with broad spectral features, based on ARPES and resistivity data.

Contribution

It reveals a new phase boundary in the phase diagram of high-temperature superconductor Bi2Sr2CaCu2O8+delta, distinguishing coherent and incoherent electronic excitations.

Findings

Coherent phase shows two spectral peaks and superlinear resistivity.

Incoherent phase exhibits broad spectral features and linear resistivity.

A new crossover line separates these two phases in the phase diagram.

Abstract

Angle resolved photoemission spectroscopy (ARPES) and resistivity measurements are used to explore the overdoped region of the high temperature superconductor Bi2Sr2CaCu2O8+delta. We find evidence for a new crossover line in the phase diagram between a coherent metal phase for lower temperatures and higher doping, and an incoherent metal phase for higher temperatures and lower doping. The former is characterized by two well-defined spectral peaks in ARPES due to coherent bilayer splitting and superlinear behavior in the resistivity, whereas the latter is characterized by a single broad spectral feature in ARPES and a linear temperature dependence of the resistivity.