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High efficiency spin-valve and spin-filter in a doped rhombic graphene quantum dot device

, , , , , , and . JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, (2018)
DOI: 10.1016/j.jmmm.2017.11.089

Abstract

Spin-polarized transport through a rhombic graphene quantum dot (rGQD) attached to armchair graphene nanoribbon (AGNR) electrodes is investigated by means of the Green's function technique combined with single-band tight-binding (TB) approach including a Hubbard-like term. The Hubbard repulsion was included within the mean-field approximation. Compared to anti-ferromagnetic (AFM), we show that the ferromagnetic (FM) ordering of the rGQD corresponds to a smaller bandgap, thus resulting in an efficient spin injector. As a consequence, the electron transport spectrum reveals a spin valve effect, which is controlled by doping with B/N atoms creating a p-n-type junction. The calculations point out that such systems can be used as spin-filter devices with efficiency close to a 100%. (C) 2017 Elsevier B.V. All rights reserved.

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