Department of Physics & Astronomy

[Dongjin Oh and Prof. Changyoung Kim] B1g-Phonon Anomaly Driven by Fermi Surface Instability at Intermediate Temperature in YBa2Cu3O7-δ

December 30, 2021l Hit 43

We performed temperature- and doping-dependent high-resolution Raman spectroscopy experiments on YBa2Cu3O7-δ to study B1g phonons. The temperature dependence of the real part of the phonon self-energy shows a distinct kink at T = TB1g above Tc due to softening, in addition to the one due to the onset of the superconductivity. TB1g is clearly different from the pseudogap temperature with a maximum in the underdoped region and resembles charge density wave onset temperature, TCDW. We attribute the B1g-phonon softening to an energy gap on the Fermi surface induced by a charge density wave order, which is consistent with the results of a recent electronic Raman scattering study. Our work demonstrates a way to investigate Fermi surface instabilities above Tc via phonon Raman studies.

Authors: Dongjin Oh, Dongjoon Song, Younsik Kim, Shigeki Miyasaka, Setsuko Tajima, Jin Mo Bok, Yunkyu Bang, Seung Ryong Park, and Changyoung Kim


Publication date: 29 December 2021