Roles of quantum interference in modulating the spin-polarized transport induced by single-helical molecules

We investigate the spin-polarized transport through the systems with protein-like single-helical molecules. It shows that the spin polarization property and efficiency tightly depend on the geometries of the systems of single-helical molecules. When one molecule is serially coupled to two leads, the inter-lead coupling assists to magnify the spin polarization efficiency, and the polarization direction can be adjusted by the local magnetic flux. However in the other geometries, no apparent spin polarization is driven, such as the T-shaped structure with inter-lead coupling and parallel coupled structures. These results reflect the nontrivial effect of structure-dependence quantum interference on the spin polarization driven by the single-helical molecule.