Flat-band spin dynamics and phonon anomalies of the saw-tooth spin-chain system Fe2O(SeO3)2

authored by
V. P. Gnezdilov, Yu G. Pashkevich, V. S. Kurnosov, O. V. Zhuravlev, D. Wulferding, P. Lemmens, D. Menzel, E. S. Kozlyakova, A. Yu Akhrorov, E. S. Kuznetsova, P. S. Berdonosov, V. A. Dolgikh, O. S. Volkova, A. N. Vasiliev

Fe3+ S=5/2 ions form saw-tooth-like chains along the a axis of the oxoselenite Fe2O(SeO3)2 and an onset of long-range magnetic order is observed for temperatures below TC=105 K. This order leads to distinct fingerprints in phonon mode linewidths and energies as resolved by Raman scattering. In addition, new excitations with small linewidths emerge below T=150 K, and are assigned to two-magnon scattering processes with the participation of flat-band and high energy magnon branches. From this a set of exchange coupling constants is estimated. The specific ratio of the saw-tooth spine-spine and spine-vertex interactions may explain the instability of the dimer quantum ground state against an incommensurate 3D magnetic order.

External Organisation(s)
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine
Technische Universität Braunschweig
National Academy of Sciences in Ukraine
Lomonosov Moscow State University
National University of Science and Technology MISIS
South Ural State University
Physical Review B
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Electronic version(s)
https://doi.org/10.1103/PhysRevB.99.064413 (Access: Unknown)