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

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:451

Article

Silva, P. V.^1,2  Saraiva-Souza, A.²  Maia, D. W.²  Souza, F. M.³  Souza Filho, A. G.¹  Meunier, V.⁴  Girao, E. C.² 

[1] Univ Fed Ceara, Dept Fis, POB 6030, BR-60455900 Fortaleza, Ceara, Brazil

[2] Univ Fed Piaui, Dept Fis, BR-64049550 Teresina, Piaui, Brazil

[3] Univ Fed Uberlandia, Inst Fis, BR-38400902 Uberlandia, MG, Brazil

[4] Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY USA

关键词: Rhombic-GQD;    11-AGNR;    Molecular electronics;    NEGF-DFT;    Electron transport;   

DOI  :  10.1016/j.jmmm.2017.11.089

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

Free