"Charge-orbital-lattice coupling effects in the dd excitation profile of one-dimensional cuprates"

J. J. Lee: B. Moritz, W. S. Lee, M. Yi, C. J. Jia, A. P. Sorini, K. Kudo, Y. Koike, K. J. Zhou, C. Monney, V. Strocov, L. Patthey, T. Schmitt, T. P. Devereaux, and Z. X. Shen; Physical Review B, 01/09/14.

Additional Authors: B. Moritz, W. S. Lee, M. Yi, C. J. Jia, A. P. Sorini, K. Kudo, Y. Koike, K. J. Zhou, C. Monney, V. Strocov, L. Patthey, T. Schmitt, T. P. Devereaux, and Z. X. Shen

Abstract:

We identify dd excitations in the quasi-one-dimensional compound Ca2Y2Cu5O10 using resonant inelastic x-ray scattering. By tuning across the Cu L3 edge, we observe abrupt shifts in the dd -peak positions as a function of incident photon energy. This observation demonstrates orbital-specific coupling of the high-energy excited states of the system to the low-energy degrees of freedom. A Franck-Condon treatment of electron-lattice coupling, consistent with other measurements in this compound, reproduces these shifts, explains the Gaussian line shapes, and highlights charge-orbital-lattice renormalization in the high-energy d manifold.