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 V 3d band shows a clear momentum-dependent modulation with the periodicity of pi, 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.