Anomalous multi-order Raman scattering in LaMnO3: a signature of quantum lattice effects in a Jahn-Teller crystal
journal contribution
posted on 2014-11-30, 11:24authored byNatalia Kovaleva, Olga Kusmartseva, K.I. Kugel, A.A. Maksimov, D. Nuzhnyy, A.M. Balbashov, E.I. Demikhov, A. Dejneka, V.A. Trepakov, Feodor Kusmartsev, Arthur Marshall Stoneham
The multi-order Raman scattering is studied up to a fourth order for
a detwinned LaMnO3 crystal. Based on a comprehensive data analysis of the
polarisation-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 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. We suggest that superexchange interaction may be crucial in
driving the system to the regime of the dynamic Jahn-Teller effect, with affordable
barriers for the tunneling between the potential energy minima.
Funding
This work was supported by the ESF network-program AQDJJ, the Royal Society
of London (grant JP 090710), the Russian Foundation for Basic Research (projects10-
02-92600-KO and 11-02-00708), Program of the Presidium RAS “Quantum mesoscopic
and disordered systems”, grant TA01010517 of the TACR (Technology Agency of the
Czech Republic), and AV0Z10100522 of the ASCR (Academy of Sciences of the Czech
Republic).
History
School
Science
Department
Physics
Published in
JOURNAL OF PHYSICS-CONDENSED MATTER
Volume
25
Issue
15
Pages
? - ? (8)
Citation
KOVALEVA, N.N. ... [et al.], 2013. Anomalous multi-order Raman scattering in LaMnO3: a signature of quantum lattice effects in a Jahn-Teller crystal. Journal of Physics: Condensed Matter, 25 (15), no. 155602.
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