Doping dependence of the many-body effects along the nodal direction in the high-Tc cuprate (Bi,Pb)_2Sr_2CaCu_2O_8

TL;DR

This study uses ARPES to explore how doping levels affect the quasiparticle dynamics and many-body interactions in high-Tc cuprates, revealing different energy dependences of scattering rates and a consistent mass renormalization.

Contribution

It provides detailed doping-dependent analysis of quasiparticle scattering and mass renormalization in high-Tc cuprates using ARPES, highlighting the evolution of many-body effects.

Findings

Linear energy dependence of scattering rate in underdoped samples

Quadratic energy dependence in overdoped samples

Mass enhancement factor around 2 at the Fermi energy

Abstract

Angle-resolved photoemission spectroscopy (ARPES) is used to study the doping dependence of the lifetime and the mass renormalization of the low energy excitations in the high-Tc cuprate (Bi,Pb)_2Sr_2CaCu_2O_8 along the zone diagonal. We find a linear energy de-pendence of the scattering rate for the underdoped samples and a quadratic energy depend-ence in the overdoped case. The mass enhancement of the quasiparticles due to the many body effects at the Fermi energy is found to be in the order of 2 and the renormalization extends over a large energy range for both the normal and the superconducting state. The much discussed kink in the dispersion around 70 meV is interpreted as a small additional effect at low temperatures.