Single-particle excitations in one-dimensional mott-hubbard insulator NaV₂O₅

We have made an angle-resolved photoemission study of NaV₂O₅ at room temperature, i.e., in the paramagnetic phase well above the spin-Peierls transition temperature. The obtained results reflect the one dimensionality of the electronic structure. The lower binding energy side of the V3d band shows a clear momentum-dependent modulation with the periodicity of π, indicating the existence of antiferromagnetic correlations or holon excitations in the one-dimensional Mott insulator. We compare the results with recent theoretical works on the one-dimensional Hubbard and t- J models and discuss consistency between model parameters.