Probing ultrafast photo-induced dynamics of the exchange energy in a Heisenberg antiferromagnet
Probing ultrafast photo-induced dynamics of the exchange energy in a Heisenberg antiferromagnet
复制标题
DOI：
10.1038/nphoton.2015.121
复制
发表时间：
2015-08-01
期刊：
影响因子：
35
通讯作者：
Scopigno, T.
中科院分区：
文献类型：
--
作者：
Batignani, G.;Bossini, D.;Scopigno, T.
使用超短光脉冲操纵固体的宏观相已经产生了壮观的现象，包括金属-绝缘体转变（1-3），超导性（4）和磁序的亚皮秒修改（5）。该研究领域的发展在很大程度上取决于对凝聚态物质中基本相互作用，特别是交换相互作用的理解和光学控制。然而，解开交换相互作用和自旋动力学对交换能E-exr的贡献相关的时间尺度是一个挑战。在这里，我们介绍飞秒受激拉曼散射解开超快光致动力学的磁激发在边缘的布里渊区。我们发现飞秒激光激发反铁磁体KNiF 3引起双磁振子线的光谱移动，其能量与E-ex成正比。通过从主要的非线性光学效应中解释光诱导的双磁振子线频率的改变，我们发现电磁刺激使E-ex增加。
Manipulating the macroscopic phases of solids using ultrashort light pulses has resulted in spectacular phenomena, including metal-insulator transitions(1-3), superconductivity(4) and subpicosecond modification of magnetic order(5). The development of this research area strongly depends on the understanding and optical control of fundamental interactions in condensed matter, in particular the exchange interaction. However, disentangling the timescales relevant for the contributions of the exchange interaction and spin dynamics to the exchange energy, E-exr is a challenge. Here, we introduce femtosecond stimulated Raman scattering to unravel the ultrafast photoinduced dynamics of magnetic excitations at the edge of the Brillouin zone. We find that femtosecond laser excitation of the antiferromagnet KNiF3 triggers a spectral shift of the two-magnon line, the energy of which is proportional to E-ex. By unravelling the photo-induced modification of the twomagnon line frequency from a dominating nonlinear optical effect, we find that E-ex is increased by the electromagnetic stimulus.