Resonant inelastic x-ray scattering study of charge excitations in La(2)CuO(4).
We report a resonant inelastic x-ray scattering study of the dispersion relations of charge-transfer excitations in insulating La(2)CuO(4).. These data reveal two peaks, both of which show two-dimensional characteristics. The lowest energy excitation has a gap energy of approximately 2.2 eV at the zone enter, and a dispersion of approximately 1 eV. The spectral weight of this mode becomes dramatically smaller around (pi, pi). The second peak shows a smaller dispersion ( approximately 0.5 eV) with a zone-center energy of approximately 3.9 eV. We argue that these are both highly dispersive exciton modes damped by the presence of the electron-hole continuum.
Kim
Y J
YJ
Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA.
Hill
J P
JP
Burns
C A
CA
Wakimoto
S
S
Birgeneau
R J
RJ
Casa
D
D
Gog
T
T
Venkataraman
C T
CT