Eur. Phys. J. Plus (2013) 128: 131
https://doi.org/10.1140/epjp/i2013-13131-0

Regular Article

Ab initio investigation of spin-filter effects in GaN nanowires with transitional metal impurities

¹ Faculty of Physics, “Materials and Devices for Electronics and Optoelectronics” Research Center, University of Bucharest, P.O. Box MG-11, 077125, Măgurele-Ilfov, Romania
² Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, 077126, Măgurele-Ilfov, Romania

^* e-mail: nemnes@solid.fizica.unibuc.ro

Received: 21 November 2012
Revised: 30 September 2013
Accepted: 11 October 2013
Published online: 5 November 2013

Abstract

The spin transport properties in gallium nitride nanowires with transitional metal impurities are investigated using first principles calculations. We focus on the spin-filter effects, which arise by introducing one or two substitutional magnetic impurities. Performing constrained spin density functional calculations we analyze both ferro- and antiferro-magnetic configurations. The spin-dependent transmission functions are calculated using the non-equilibrium Green’s functions formalism. The contribution of the surface states to the spin transport is pointed out, with a particular emphasis on their role in reducing the wide band gap of the III-V semiconductor. Different transitional metal impurities are introduced and the spin separation is evaluated. The feasibility of using GaN nanowires in realistic applications is further analyzed, by attaching Al(111) nanoscopic contacts. The obtained polarization of the spin current reveals the suitability of the considered structures in viable spintronic devices.