Department of Applied Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Phys Rev Lett. 2010 Apr 30;104(17):177206. doi: 10.1103/PhysRevLett.104.177206.
We study theoretically the electromagnon and its optical spectrum (OS) of the terahertz-frequency regime in the magnetic-spiral-induced multiferroic phases of the rare-earth-metal (R) Mn perovskites, RMnO3, taking into account the spin-angle modulation or the higher harmonics of the spiral spin configuration, which has been missed so far. A realistic spin Hamiltonian, which gives phase diagrams in agreement with experiments, resolves a puzzle, i.e., the double-peak structure of the OS with a larger low-energy peak originating from magnon modes hybridized with the zone-edge state. We also predict the magnon branches associated with the electromagnon, which can be tested by neutron-scattering experiment.
我们从理论上研究了在考虑到迄今被忽略的螺旋自旋结构的自旋角调制或更高次谐波的情况下，在稀土金属(R)锰钙钛矿 RMnO3 的磁螺旋诱导多铁相中的太赫兹频率范围内的电磁子及其光学谱(OS)。一个与实验一致的现实的自旋哈密顿量解决了一个难题，即 OS 的双峰结构，其中较低能量的峰较大，源自与带边态混合的磁子模式。我们还预测了与电磁子相关的磁子分支，这些分支可以通过中子散射实验来验证。
