The S = 1/2 antiferromagnetic dimer system CsV2O5 has a nonmagnetic singlet ground state and a finite energy gap to triplet excited states. CsV2O5 is composed of magnetic dimer units of V4+ along the chain, with exchange interaction J0 occurring between two structural dimers.
In this study, we investigate the magnetic properties of the layered compound CsV2O5 using magnetic susceptibility measurements and powder inelastic neutron scattering. DC susceptibility is measured across various temperature ranges and analyzed using both isolated and interacting dimer models. From the susceptibility data, the exchange interaction J0 is determined to be 12.45 meV. However, DC susceptibility struggles to accurately describe the interdimer interactions.
The inelastic neutron scattering results quantitatively confirm that CsV2O5 has an energy gap ∆ = 10 meV, with a bandwidth of excitations of 4.98 meV. Random phase approximation indicates that the behavior of this system is much closer to that of a two-dimensionally interacting dimer with J′ = 9.98 meV with significant interdimer and interchain couplings than that of isolated or alternating dimers as was initially proposed. The ratio of interdimer to intradimer exchange constants is J′/J0 = 0.80. A comparison to the DFT measurement is discussed
