Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.
Phys Chem Chem Phys. 2019 Apr 3;21(14):7256-7260. doi: 10.1039/c8cp07786j.
In current materials science and technologies, surface effects on carrier and spin dynamics in functional materials and devices are of great importance. In this paper, we present the surface-sensitive probing of electron spin dynamics, performed by optical-pump-probe scanning tunneling microscopy (OPP-STM). Time-resolved spin lifetime information on a manganese (Mn)-deposited GaAs(110) surface was successfully obtained for the first time. With increasing Mn density via in situ evaporation, a nonlinear change in the spin lifetime in the picosecond range was clearly observed, while directly confirming the Mn density by STM. In comparison with the results obtained by the conventional OPP method, we have also demonstrated that the observed nonlinear spin lifetime behavior was surface-mediated, which can be characterized using only the surface-sensitive OPP-STM technique.
在当前的材料科学和技术中，功能材料和器件中载流子和自旋动力学的表面效应非常重要。本文通过光学泵浦-探测扫描隧道显微镜（OPP-STM）展示了对电子自旋动力学的表面敏感探测。首次成功获得了锰（Mn）沉积在 GaAs(110)表面上的自旋寿命的时间分辨信息。通过原位蒸发增加 Mn 的密度，在皮秒范围内明显观察到自旋寿命的非线性变化，同时通过 STM 直接确认 Mn 的密度。与传统的 OPP 方法的结果相比，我们还证明了观察到的非线性自旋寿命行为是表面介导的，这可以仅使用表面敏感的 OPP-STM 技术来表征。
