Coupled Spin-Phonon Excitations in Helical Multiferroics - Condensed Matter > Strongly Correlated ElectronsReport as inadecuate




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Abstract: Both the Dzyaloshiskii-Moriya interaction and the exchange-striction areshown to affect dynamically the magnetoelectric excitations in the perovskitemultiferroic RMnO3. The exchange-striction results in a biquadratic interactionbetween the spins and the transverse phonons, giving rise to quantumfluctuations of the ferroelectric polarization P. This leads to low-lyingphonon modes that are perpendicular to P and to the helical spins at small wavevector but are parallel to P at a wave vector close to the magnetic modulationvector. For spin-1-2 helimagnet, the local polarization can be completelyreversed by the spin fluctuation, and so does the direction of the on-site spinchirality, which allows for a finite differential scattering intensity ofpolarized neutrons from a cycloidal magnet.



Author: Chenglong Jia, Jamal Berakdar

Source: https://arxiv.org/







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