Ali M Keshtan M, Esmaeilzadeh Mahdi
Department of physics, Iran University of Science and Technology, Narmak, Tehran 16844, Iran.
J Phys Condens Matter. 2020 May 27;32(34). doi: 10.1088/1361-648X/ab832a.
Using the Su-Schrieffer-Heeger Hamiltonian and exploiting the Green's function method in the framework of the Landauer-Büttiker formalism, the topological and spin dependent electron transport properties of a trans polyacetylene molecule are studied. It is found that molecules with the intracell single carbon-carbon bonding and the even number of monomers in their chains have two edge states and possess topological properties though their Hamiltonians do not respect the chiral symmetry. A perpendicular exchange magnetic field and two perpendicular and transverse electric fields are used to induce and manipulate the quantum spin dependent electron transport properties. The exchange field induces the spin polarization in different electron energy regions which are expanded by stronger exchange fields. Therefore this proposed device works as a perfect spin filter. The spin polarization can be manipulated by applying the perpendicular electric field and remains robust against the transverse electric field variations.
利用Su-Schrieffer-Heeger哈密顿量，并在Landauer-Büttiker形式体系的框架内运用格林函数方法，研究了反式聚乙炔分子的拓扑和自旋相关电子输运性质。研究发现，链内具有单碳-碳键且链中单体数量为偶数的分子有两个边缘态，尽管其哈密顿量不满足手征对称性，但仍具有拓扑性质。利用垂直交换磁场以及两个垂直和横向电场来诱导和操纵与量子自旋相关的电子输运性质。交换场在不同电子能量区域诱导自旋极化，更强的交换场会使这些区域扩展。因此，该提议的器件可作为一个完美的自旋滤波器。通过施加垂直电场可操纵自旋极化，并且其对横向电场变化具有鲁棒性。
