Photoemission Studies on Bi2Sr2CaCuZnO - Electronic Structure Evolution and Temperature Dependence

TL;DR

This study uses angle-resolved photoelectron spectroscopy to investigate how Zn substitution affects the electronic structure and superconductivity in Bi2Sr2CaCuZnO, revealing suppression of spectral peaks, changes in the superconducting gap, and temperature-dependent spectral modifications.

Contribution

It provides new insights into how Zn doping influences the electronic structure and superconducting properties of Bi2Sr2CaCuZnO, highlighting the role of impurity location and local charge inhomogeneity.

Findings

Zn suppresses spectral peaks along (0,0) to (pi,pi)

Superconducting Tc remains as high as 83K despite Zn doping

Zn enhances temperature-induced spectral changes and charge inhomogeneity

Abstract

An angle resolved photoelectron spectroscopy study was conducted on BiSrCaCuZnO. A small amount of Zn substitution for Cu almost completely suppresses the otherwise sharp spectral peak along the (0,0) to (pi,pi) direction in BiSrCaCuZnO, while superconductivity with Tc as high as 83K survives. This behavior contrasts markedly from that seen in cases where the impurities are located off the CuO plane, as well as when the CuO planes are underdoped. This effect is also accompanied by changes of low energy excitations at (pi,0), near the anti-node position of the d-wave pairing state. With Zn doping the size of the superconducting gap is significantly suppressed, the width of the quasiparticle peak in the superconducting state becomes wider, and the dip at higher binding energy is diminished. In addition, enhanced temperature induced spectral changes also occur. We show intriguing systematic lineshape changes with temperature that persist to a very high energy scale - a result consistent with the idea that Zn enhances the local charge inhomogeneity.