...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Physics, D. Applied Physics: A Europhysics Journal >Ultrafast dynamics at lanthanide surfaces: microscopic interaction of the charge, lattice and spin subsystems
【24h】

Ultrafast dynamics at lanthanide surfaces: microscopic interaction of the charge, lattice and spin subsystems

机译：镧系元素表面的超快动力学：电荷，晶格和自旋子系统的微观相互作用

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In solids the charge, lattice and spin degrees of freedom are coupled and the respective coupling strengths result in characteristic timescales on which excitations of one particular subsystem interact and equilibrate with the remaining subsystems. In ferromagnetic metals the respective elementary interaction processes occur on the pico- and femtosecond time scales. To elucidate these interaction mechanisms and the timescales we investigate the ultrafast dynamics of electrons, phonons and spins excited by an intense infrared optical pulse at Gd(0 0 0 1) and Tb(0 0 0 1) surfaces, employing complementary time-resolved methods of optical second harmonics generation and photoelectron spectroscopy. These surfaces exhibit rich dynamics including a collective response of the crystal lattice and the magnetization, manifested by a coupled coherent optical phonon–magnon mode at 3 THz. After a review of the earlier studies we present temperature- and fluence-dependent results of pump–probe experiments. The temperature dependence of the coherent phonon (CP) amplitude shows that a spin- and a charge-driven excitation mechanism can be separated. The spin-driven excitation dominates below the Curie temperature in agreement with ab initio model calculations that establish a displacement of the surface plane upon a change of the surface spin polarization. Analysis of the temperature-dependent CP damping shows an anomaly in the vicinity of the Curie temperature that is for Gd well described by phonon–magnon scattering. In the case of Tb an additional damping channel is required that could be related to local spin-flip excitations.
机译：在固体中，电荷，晶格和自旋自由度是耦合的，各自的耦合强度会导致特征性的时标，在该时标上，一个特定子系统的激发与其余子系统相互作用并达到平衡。在铁磁金属中，各自的基本相互作用过程在皮秒和飞秒的时间尺度上发生。为了阐明这些相互作用机理和时间尺度，我们采用互补的时间分辨方法，研究了由强红外光脉冲在Gd（0 0 0 1）和Tb（0 0 0 1）表面激发的电子，声子和自旋的超快动力学。二次谐波的产生和光电子光谱学这些表面表现出丰富的动力学特性，包括晶格和磁化的集体响应，表现为3 THz的相干相干光子-磁振子耦合模式。在回顾了较早的研究之后，我们提出了泵探针实验与温度和注量有关的结果。相干声子（CP）幅度的温度依赖性表明，自旋和电荷驱动的激励机制可以分开。自旋驱动的激发在居里温度以下占主导地位，这与从头算模型计算相符，后者在表面自旋极化改变时建立了表面平面的位移。对温度相关的CP阻尼的分析显示，居里温度附近存在一个异常，这是声子-马农散射对Gd的很好描述。在Tb的情况下，需要一个附加的阻尼通道，该通道可能与局部自旋翻转激励有关。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号