论文标题
界面电子反射的异常空间变化超出线性近似
Anomalous spatial shifts in interface electronic reflection beyond linear approximation
论文作者
论文摘要
最近,包括Goos-Hänchen和Imbert-Fedorov效应在内的异常空间转移的电子类比引起了广泛的兴趣。当前对界面电子反射异常空间变化的研究基于线性近似的范式,在该范围内,通过扩展相关基态状态的相位和散射幅度到一阶事件动量的一阶,从而获得了入射和反射梁的中心位置和反射梁。但是,在一类正常情况下,线性近似可能会导致某些入射角反射的空间变化,即使相应的反射可能性是有限的。在这项工作中,我们表明这种非物理结果是由于临界参数处的传播状态数的突然变化引起的,并且可以通过计算超出线性近似之外的散射光束的中心位置来解决。此外,我们发现光束宽度对临界角度附近的空间移位有重要影响。我们通过在两个代表性模型上对鹅hänchen和Imbert-Fedorov转移的具体计算来证明我们的想法。这些结果有益于阐明线性近似在异常空间偏移研究中的应用范围。
Recently, the electronic analogy of the anomalous spatial shift, including Goos-Hänchen and Imbert-Fedorov effects, has been attracting widespread interest. The current research on the anomalous spatial shift in interface electronic reflection is based on the paradigm of linear approximation, under which the center position of the incident and reflected beams are obtained by expanding the phases of relevant basis states and scattering amplitudes to the first order of incident momentum. However, in a class of normal cases, the linear approximation can lead to a divergent spatial shift in reflection for certain incident angles even though the corresponding reflection possibility is finite. In this work, we show that such non-physical results are caused by an abrupt change in the number of the propagating states at critical parameters, and can be resolved by calculating the center positions of the scattering beams beyond the linear approximation. Moreover, we find that the beam width has an important influence on the spatial shift near the critical angles. We demonstrate our idea via concrete calculations of Goos-Hänchen and Imbert-Fedorov shift on two representative models. These results are beneficial for clarifying the scope of application of the linear approximation in the study of anomalous spatial shifts.