Dynamics of the two-dimensional S=1/2 dimer system (C5H6N2F)2CuCl4

TL;DR

This study investigates the magnetic excitation spectrum of a 2D S=1/2 antiferromagnetic dimer system using inelastic neutron scattering, revealing a gapped spectrum and exchange interactions consistent with a weakly-coupled square lattice model.

Contribution

First detailed experimental characterization of the magnetic excitations in this specific 2D dimer system using neutron scattering.

Findings

Identified a 1.07 meV energy gap in magnetic excitations.

Determined intra-dimer exchange J=1.45 meV and inter-dimer J'=0.31 meV.

Confirmed the dispersion relation aligns with a 2D square lattice of dimers.

Abstract

Inelastic neutron scattering was used to study a quantum S=1/2 antiferromagnetic Heisenberg system-Bis(2-amino-5-fluoropyridinium) Tetrachlorocuprate(II). The magnetic excitation spectrum was shown to be dominated by long-lived excitations with an energy gap as 1.07(3) meV. The measured dispersion relation is consistent with a simple two-dimensional square lattice of weakly-coupled spin dimers. Comparing the data to a random phase approximation treatment of this model gives the intra-dimer and inter-dimer exchange constants J=1.45(2) meV and J'=0.31(3) meV, respectively.