Anomalous multi-order Raman scattering in LaMnO3: a signature of quantum lattice effects in a Jahn-Teller crystal

作者：Kovaleva N N^*; Kusmartseva O E; Kugel K I; Maksimov A A; Nuzhnyy D; Balbashov A M; Demikhov E I; Dejneka A; Trepakov V A; Kusmartsev F V; Stoneham A M

来源：Journal of Physics: Condensed Matter , 2013, 25(15): 155602.

DOI：10.1088/0953-8984/25/15/155602

The multi-order Raman scattering is studied up to fourth order for a detwinned LaMnO3 crystal. Based on a comprehensive data analysis of the polarization-dependent Raman spectra, we show that the anomalous features in the multi-order scattering could be the sidebands on the low-energy mode at about 25 cm(-1). We suggest that this low-energy mode stems from the tunneling transition between the potential energy minima arising near the Jahn-Teller Mn3+ ion due to the lattice anharmonicity and that the multi-order scattering is activated by this low-energy electronic motion. The sidebands are dominated by the oxygen contribution to the phonon density-of-states, however, there is an admixture of an additional component, which may arise from coupling between the low-energy electronic motion and the vibrational modes.

• 出版日期2013-4-17