Linear dependence of peak width in $\chi(\bq, \omega)$ vs T_c for YBCO superconductors

TL;DR

This paper demonstrates a linear relationship between the momentum space width of the spin susceptibility peak and the superconducting transition temperature in YBCO superconductors, highlighting similarities with LaSrCuO.

Contribution

It establishes a direct proportionality between peak width in spin susceptibility and T_c, revealing a universal magnetic feature across cuprate superconductors.

Findings

Peak width in Im$hi(q,)$ is linearly proportional to T_c.

The velocity ar v^* is approximately 35 meVb7c5 and consistent across doping levels.

Magnetic properties of YBCO are similar to those of LaSrCuO.

Abstract

It is shown that the momentum space width of the peak in the spin susceptibility, Im$\chi(q,\omega)$, is linearly proportional to the superconducting $T_c$: $T_c = \hbar v^*\Delta q$ with $\hbar v^* \simeq 35 meV$\AA. This relation is similar to the linear relation between incommensurate peak splitting and $T_c$ in LaSrCuO superconductors, as first proposed by Yamada et al. (Phys. Rev. B 57, 6165, (1998)). The velocity $\hbar v^*$ is smaller than Fermi velocity or the spin-wave velocity of the parent compound and remains the same for a wide doping range. This result points towards strong similarities in magnetic state of YBCO and LaSrCuO.