"Decoupling spin-orbital correlations in a layered manganite amidst ultrafast hybridized charge-transfer band excitation"

L. Shen: S. A. Mack, G. Dakovski, G. Coslovich, O. Krupin, M. Hoffmann, S.-W. Huang, Y-D. Chuang, J. A. Johnson, S. Lieu, S. Zohar, C. Ford, M. Kozina, W. Schlotter, M. P. Minitti, J. Fujioka, R. Moore, W-S. Lee, Z. Hussain, Y. Tokura, P. Littlewood, and J. J. Turner; Physical Review B, 05/12/20.

Additional Authors: S. A. Mack, G. Dakovski, G. Coslovich, O. Krupin, M. Hoffmann, S.-W. Huang, Y-D. Chuang, J. A. Johnson, S. Lieu, S. Zohar, C. Ford, M. Kozina, W. Schlotter, M. P. Minitti, J. Fujioka, R. Moore, W-S. Lee, Z. Hussain, Y. Tokura, P. Littlewood, and J. J. Turner

Abstract:

In the mixed-valence manganites, a near-infrared laser typically melts the orbital and spin order simultaneously, corresponding to the photoinduced d1d→ d0d1 excitations in the Mott-Hubbard bands of manganese. Here, we use ultrafast methods—both femtosecond resonant x-ray diffraction and optical reflectivity—to demonstrate that the orbital response in the layered manganite Nd1−xSr1+xMnO4 (x = 2/3) does not follow this scheme. At the photoexcitation saturation fluence, the orbital order is only diminished by a few percent in the transient state. Instead of the typical d1d→ d0d1 transition, a near-infrared pump in this compoundpromotes a fundamentally distinct mechanism of charge transfer, the d0 →  d1L, where L denotes a hole in the oxygen band. This finding may pave a different avenue for selectively manipulating specific types of order in complex materials of this class.