Magnonlike dispersion of spin resonance in Ni-doped BaFe$_2$As$_2$

TL;DR

This study reveals a magnon-like upward dispersion of spin resonance in Ni-doped BaFe$_2$As$_2$, showing anisotropic behavior within the Fe layer, contrasting with cuprate superconductors.

Contribution

It demonstrates the magnon-like dispersion of spin resonance in electron-doped BaFe$_2$As$_2$, highlighting anisotropic dispersion and contrasting with cuprate behaviors.

Findings

Resonance is sharply peaked at Q_{AFM} along the orthorhombic a axis.

Resonance disperses upwards away from Q_{AFM} along the b axis.

The resonance exhibits a magnon-like upward dispersion, unlike cuprates.

Abstract

Inelastic neutron scattering measurements on Ba(Fe$_{0.963}$Ni$_{0.037}$)$_2$As$_2$ manifest a neutron spin resonance in the superconducting state with anisotropic dispersion within the Fe layer. Whereas the resonance is sharply peaked at Q$_{AFM}$ along the orthorhombic a axis, the resonance disperses upwards away from Q$_{AFM}$ along the b axis. In contrast to the downward dispersing resonance and hour-glass shape of the spin excitations in superconducting cuprates, the resonance in electron-doped BaFe$_2$As$_2$ compounds possesses a magnon-like upwards dispersion.