Abstract
Raman scattering is used to observe pronounced electronic excitations around 230 meV—well above the two-phonon range—in the Mott insulators and . Based on the temperature, polarization, and photon energy dependence, the modes are identified as orbital excitations. The observed profiles bear a striking resemblance to magnetic Raman modes in the insulating parent compounds of the superconducting cuprates, indicating an unanticipated universality of the electronic excitations in transition metal oxides.
- Received 28 February 2005
DOI:https://doi.org/10.1103/PhysRevLett.97.157401
©2006 American Physical Society