Scientific Reports_4_6157_spin carbon chain.pdfVIP

High performance current and spin diode of atomic carbon chain between transversely symmetric ribbon electrodes Yao-Jun Dong1, Xue-Feng Wang1,2, Shuo-Wang Yang3 Xue-Mei Wu1,2 1College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, China, 2State Key Laboratory of Functional Materials for Informatics and Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China, 3Institute of High Performance Computing, A*Star, 1 Fusionopolis Way, 16-16 Connexis, Singapore 138632, Singapore. We demonstrate that giant current and high spin rectification ratios can be achieved in atomic carbon chain devices connected between two symmetric ferromagnetic zigzag-graphene-nanoribbon electrodes. The spin dependent transport simulation is carried out by density functional theory combined with the non-equilibriumGreen’s functionmethod. It is found that the transverse symmetries of the electronic wave functions in the nanoribbons and the carbon chain are critical to the spin transport modes. In the parallel magnetization configuration of two electrodes, pure spin current is observed in both linear and nonlinear regions. However, in the antiparallel configuration, the spin-up (down) current is prohibited under the positive (negative) voltage bias, which results in a spin rectification ratio of order 104. When edge carbon atoms are substituted with boron atoms to suppress the edge magnetization in one of the electrodes, we obtain a diode with current rectification ratio over 106. T he current rectification in a diode is fundamental in electronics and the spin current rectification is equally important in spintronics. In the diffusive transport regime, various charge and spin diodes have been proposed1–4. Since the pioneer work done byAviram andRatner onmolecular rectifier5, rectification systems in atomistic scale have been extensively studie