Uncovering a pressure-tuned electronic transition in BiSrYCu2O8 using Raman scattering and x-ray diffraction

TL;DR

This study identifies a critical pressure at 21 GPa in BiSrYCu2O8 where electronic, lattice, and magnetic properties all exhibit anomalies, indicating a pressure-induced electronic transition similar to doping effects in cuprates.

Contribution

First demonstration of simultaneous anomalies in charge, lattice, and magnetic properties at a specific pressure in a cuprate, linking pressure effects to doping-like electronic transitions.

Findings

Anomalies observed at 21 GPa in Raman and x-ray data.

Correlation between pressure-induced and doping-induced electronic states.

Evidence of a pressure-tuned electronic transition in cuprates.

Abstract

We report pressure tuned Raman and x-ray diffraction data of Bi1.98Sr2.06Y0.68Cu2O8 revealing a critical pressure at 21 GPa with anomalies in six physical quantities: electronic Raman background, electron-phonon coupling, spectral weight transfer from high to low frequency, density dependent behaviour of phonon and magnon frequencies, and a compressibility change in the c-axis. For the first time in a cuprate, mobile charge carriers, lattice, and magnetism all show anomalies at a distinct critical pressure in the same experimental setting. Furthermore, the Raman spectral changes are similar to that seen traversing the superconducting dome with doping, suggesting that the critical pressure at 21 GPa is related to the much discussed critical point at optimal doping.