Regular Article

Even–odd chain effect and quantum pumping effect induced spatial spin filter on a Y-shaped zigzag silicene nanoribbon junction

¹ Department of Applied Physics, College of Science, Nanjing Forestry University, Nanjing 210037, P.R. China
² Department of Physics and Institute of Theoretical Physics, Nanjing Normal University, Nanjing 210023, P.R. China
³ School of Physics and Electronic Engineering, Linyi University, Linyi 276005, P.R. China

^a e-mail: lzhang2010@163.com

Received: 25 June 2020
Received in final form: 11 September 2020
Accepted: 21 September 2020
Published online: 11 November 2020

Abstract

We propose a possible spatial spin filter on a Y-shaped zigzag silicene nanoribbon (ZSNR) junction with different even(odd)-chain electrodes by applying three pumping electric fields. By means of the tight-binding model and Keldysh Green’s function method, we calculate the spin-dependent tunneling currents on the middle–left (M–L) and middle–right (M–R) terminals of Y-shaped ZSNR junction, and find that this spin pump not only can generate a pure spin current and a 100% polarized spin current at a zero bias, but also can spatially separate spin up and spin down currents on its even(odd)-chain M–L(R) terminals. The spatial spin filtering phenomena might come from the combination of the even–odd chain effect and single photon-assisted pumping process. The pumped spin up(down) current and its ON(OFF) transport states on M–L(R) terminal of the Y-shaped ZSNR junction can be modulated by almost all the device’s parameters such as the Fermi level, pumping frequency, spin–orbit coupling, staggered lattice potential and magnetization distribution. We also explore the possible way to close the spatial spin filtering behaviors in the device. Our findings might be useful for producing and separating 100% polarized spin up and down currents on multi-terminal silicene nanodevices.