Absence of static phase separation in the high-Tc cuprate $YBa_{2}Cu_{3}O_{6+y}$

TL;DR

This study uses 89Y NMR to show that static phase separation is absent in YBa2Cu3O6+y, indicating it is not a common feature across cuprate high-temperature superconductors.

Contribution

The paper provides high-sensitivity NMR evidence that static phase separation does not occur in YBa2Cu3O6+y, challenging previous observations in other cuprates.

Findings

Narrow hole doping distribution with Δp<0.025 in YBa2Cu3O6+y

No evidence of static phase separation in the studied samples

Contrasts with phase separation observed in Bi2212 and LaSrCuO

Abstract

We use 89Y NMR in $YBa_{2}Cu_{3}O_{6+y}$ in order to evaluate with high sensitivity the distribution of hole content p in the CuO2 planes. For y=1 and y=0.6, this hole doping distribution is found narrow with a full width at half maximum smaller than Delta p=0.025. This rules out any large static phase separation between underdoped and optimally doped regions in contrast with the one observed by STM in Bi2212 and by NQR in LaSrCuO. This establishes that static electronic phase separation is not a generic feature of the cuprates.