Model for twin electromagnons and magnetically induced oscillatory polarization in multiferroic RMnO3

被引：39

作者：

Stenberg, Markku P. V. ^{[1
]}

de Sousa, Rogerio ^{[1
]}

机构：

[1] Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada

来源：

PHYSICAL REVIEW B | 2009年 / 80卷 / 09期

基金：

加拿大自然科学与工程研究理事会;

关键词：

electron spin polarisation; ground states; magnetostriction; magnons; multiferroics; spin-orbit interactions; terbium compounds;

D O I：

10.1103/PhysRevB.80.094419

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We propose a model for the pair of electromagnon excitations observed in the class of multiferroic materials RMnO3 (R is a rare-earth ion). The model is based on a harmonic cycloid ground state interacting with a zone-edge magnon and its twin excitation separated in momentum space by two times the cycloid wave vector. The pair of electromagnons is activated by cross coupling between magnetostriction and spin-orbit interactions. Remarkably, the spectral weight of the twin electromagnon is directly related to the presence of a magnetically induced oscillatory polarization in the ground state. This leads to the surprising prediction that TbMnO3 has an oscillatory polarization with amplitude 50 times larger than its uniform polarization.

引用

页数：5