Charge Excitations in Nd$_{2-x}$Ce$_x$CuO$_4$ Observed with Resonant Inelastic X-ray Scattering: Comparison of Cu K-edge with Cu L$_3$-edge.

We report a Cu K-edge resonant inelastic x-ray scattering (RIXS) study of momentum-dependent charge excitations in Nd$_{2-x}$Ce$_x$CuO$_4$ ($x$ = 0.075 and 0.18). The peak position and width of the excitations coincide excellently with those observed in Cu L$_3$-edge RIXS. It demonstrates that the same charge excitations are observed at the two edges.