Resonant inelastic X-ray scattering spectrum in Hubbard ladder

Tsutsui, Kenji; Toyama, Takami*; Maekawa, Sadamichi*

We examine theoretically the resonant inelastic X-ray scattering (RIXS) in ladder system by using the exact diagonalization techniques on the single-band Hubbard ladder model. We calculate the RIXS spectrum for each momentum transfer along the leg and the rung directions, and find that the spectral feature is similar to that of the two-dimensional (2D) case. However, in contrast to the hole-doped 2D case, the momentum dependence of the RIXS for the Mott gap excitation unchanges upon doping in the ladder. We consider that the spectral feature upon doping in the ladder comes from the fact that the spin state around holes remains forming the local singlets along the rungs. The result suggests that the RIXS can provide an opportunity for revealing the hole-pairing of the ladder system.