Dispersion relation of charge gap excitations in quasi-1D Mott insulators studied by resonant X-ray scattering

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D. Qian, Y.W. Li, M.Z. Hasan, D.M. Casa, T. Gog, Y.D. Chuang, K. Tsutsui, T. Tohyama, S. Maekawa, H. Eisaki, S. Uchida

Abstract:
Momentum dependence of charge excitations across the effective Mott gap in several quasi-low-dimensional model cuprates with different effective dimensionalities is studied using high resolution inelastic X-ray scattering by working near Copper k-edge resonance which allows us to extract the dispersion relations of the particle-hole pair excitations at the gap edge. Besides electron-electron correlation, momentum dependence of the gap-excitations is found to be strongly dependent on the effective dimensionality (or topology) of the 3d(x2-y2) network. (c) 2005 Published by Elsevier Ltd.