Spin Filter of Graphene Nanoribbon Based Structure

• Published in: Chinese physics letters Vol. 27; no. 8; pp. 176 - 179
• Main Author: 万浪辉 余陨金 王斌
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.08.2010
• Subjects: Aluminum; Bias; Electric potential; Energy bands; Graphene; Nanomaterials; Nanostructure; Ribbons; 密度泛函计算; 纳米带; 自旋相关; 非平衡格林函数
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/27/8/087205

Spin-dependent transport properties of the zigzag graphene nano-ribbon （zGNR） based structure Al-zGNR-Al are investigated by ab initio technique where density functional calculation is carried out within the Keldysh non-equilibrium Green＇s function formalism. The energy band structure of the infinite zigzag ribbon is sensitive to the dangling bonds of carbon atoms on both edge sides. For the three-circle-width zigzag ribbon with one edge monohydrogenated and the other edge dihydrogenated （zGNR（H-H2））, strongly spin-polarized energy bands are found. A spin-down branch is obtained just below the Fermi level while a spin up band appears above it. For the structure Al-zGNR（H-H2）-Al, where three-circle-width and seven-circle-length （3 × 7） zGNR（H-H2） is coupled by two （100） aluminium electrodes, an obvious spin filter property is found as the bias voltage changes. When the length of the sandwiched zGNR（H-H2） ribbon increaes, the spin-up current is strongly restrained especially under higher bias voltage.