Pseudogap and incommensurate magnetic fluctuations in YBa_2Cu_3O_{6. 6}

TL;DR

This study uses neutron scattering to explore how magnetic fluctuations and the pseudogap evolve with temperature in YBa2Cu3O6.6, revealing a pseudogap opening above Tc and incommensurate fluctuations linked to it.

Contribution

It provides new insights into the relationship between the pseudogap and magnetic fluctuations in underdoped cuprates using neutron scattering.

Findings

Pseudogap opens in spin fluctuations above Tc

Incommensurate magnetic fluctuations appear with pseudogap

A spin fluctuation gap is observed in the superconducting state

Abstract

Unpolarized inelastic neutron scattering is used to study the temperature and wave vector dependence of the dynamical magnetic susceptibility, $\chi''(q,\omega)$, of a well characterized single crystal $YBa_2Cu_3O_{6.6}$ ($T_c=62.7$ K). We find that a pseudogap opens in the spin fluctuation spectrum at temperatures well above $T_c$. We speculate that the appearance of the low frequency incommensurate fluctuations is associated with the opening of the pseudogap. To within the error of the measurements, a gap in the spin fluctuation spectrum is found in the superconducting state.