Benini Leonardo, Mukherjee Amrita, Chakrabarti Arunava, Römer Rudolf A
Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
Department of Physics, University of Kalyani, Kalyani, West Bengal, 741 235, India.
Sci Rep. 2019 Apr 11;9(1):5930. doi: 10.1038/s41598-019-42316-5.
We investigate a simple tight-binding Hamiltonian to understand the stability of spin-polarized transport of states with an arbitrary spin content in the presence of disorder. The general spin state is made to pass through a linear chain of magnetic atoms, and the localization lengths are computed. Depending on the value of spin, the chain of magnetic atoms unravels a hidden transverse dimensionality that can be exploited to engineer energy regimes where only a selected spin state is allowed to retain large localization lengths. We carry out a numerical anmalysis to understand the roles played by the spin projections in different energy regimes of the spectrum. For this purpose, we introduce a new measure, dubbed spin-resolved localization length. We study uncorrelated disorder in the potential profile offered by the magnetic substrate or in the orientations of the magnetic moments concerning a given direction in space. Our results show that the spin filtering effect is robust against weak disorder and hence the proposed system should be a good candidate model for experimental realizations of spin-selective transport devices.
我们研究了一个简单的紧束缚哈密顿量，以理解在无序存在的情况下，具有任意自旋含量的态的自旋极化输运的稳定性。使一般的自旋态通过磁性原子的线性链，并计算局域化长度。根据自旋值，磁性原子链展现出一个隐藏的横向维度，可利用该维度来设计能量区域，在这些区域中只有选定的自旋态能够保持较大的局域化长度。我们进行了数值分析，以了解自旋投影在光谱的不同能量区域中所起的作用。为此，我们引入了一种新的量度，称为自旋分辨局域化长度。我们研究了由磁性衬底提供的势分布中或关于空间中给定方向的磁矩取向中的不相关无序。我们的结果表明，自旋过滤效应对于弱无序是稳健的，因此所提出的系统应该是自旋选择性输运器件实验实现的一个良好候选模型。
