On the 590cm-1 B1g feature in underdoped Bi2Sr2CaCu2O8+delta

TL;DR

This study investigates a 590cm-1 Raman feature in underdoped Bi2Sr2CaCu2O8+delta, revealing its disorder-induced vibrational origin and doping-related electronic spectral changes.

Contribution

It identifies the 590cm-1 peak as a disorder-induced vibrational mode and links underdoping to spectral weight depletion near the Brillouin zone axes.

Findings

The 590cm-1 peak softens with oxygen isotope exchange.

The peak is absent in Y-doped underdoped crystals.

Underdoping causes depletion of low-energy spectral weight.

Abstract

Raman scattering studies have been performed on underdoped Bi2Sr2CaCu2O8+delta. In single crystals underdoped by oxygen removal, a 590 cm-1 peak is observed in the B1g spectrum. The feature is observed to soften in frequency by 3.8% with isotopic exchange for 16-O by 18-O. In contrast, the 590cm-1 peak is not observed in crystals underdoped by Y substitution which suggests that it correspond to a disorder induced vibrational mode. We have also found that underdoping leads to a depletion of low energy spectral weight from regions of the Fermi surface located near the Brillouin zone axes.