Perfect spin filter and strong current polarization in carbon atomic chain with asymmetrical connecting points

¹ School of Physics and Microelectronic and Key Laboratory for Micro- Nano Physics and Technology of Hunan Province, Hunan University - Changsha 410082, PRC
² School of Optoelectronic Information, University of Electronic Science and Technology of China Chengdu, Sichuan, 610054, PRC
³ Department of Electrical and Information Engineering, Hunan Institute of Engineering - Xiangtan 411101, PRC

^(a) xfli@hnu.edu.cn
^(b) llwang@hnu.edu.cn

Received: 18 January 2014
Accepted: 27 February 2014

Abstract

The spin-dependent electron transport properties through a single-carbon atomic chain (SCAC) sandwiched between two-zigzag-graphene-nanoribbon (zGNR) electrodes are investigated by performing first-principles calculations based on the nonequilibrium Green's function (NEGF) approach in combination with spin density functional theory (DFT). Our calculations show that SCAC connecting two zGNRs with asymmetry-contacting points is a perfect spin filter in the transmission function within a large energy range. Moreover, the spin-dependent electron transmission spectra exhibit robust transport polarization characteristics and a strong current polarization behavior (almost 100%) can be found. The microscopic mechanisms are proposed for the spin-related phenomena.