Rotons and spin transport in square lattice antiferromagnets in magnetic fields

International Conference on Strongly Correlated Electron Systems 2014

Kubo, Yurika^1 ; Kurihara, Susumu^1

Department of Physics, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo

169-8555, Japan^1

关键词: Excitation spectrum;    Magnon interactions;    Nonlinear spin waves;    Saturation fields;    Spin conductivity;    Spin transport;    Square-lattice antiferromagnets;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012116/pdf
DOI  :  10.1088/1742-6596/592/1/012116

来源: IOP

【 摘 要 】

We investigate the excitation spectrum and spin conductivity in square lattice antiferromagnets by nonlinear spin-wave theory. We have found that the excitation spectrum have a rotonlike minimum at about 3/4 of the saturation field. The «roton» appears and softens rapidly to zero as a function of the magnetic field as a result of the especially strong three-magnon interactions. For the spin conductivity, it becomes clear that a two-magnon sideband appears for sufficiently strong three-magnon interactions.