Field-Controllable Spin Filter Based on Parallel Quantum Dot Systems
In this paper, we investigate the spin-polarized transport through parallel N−dot (N = 1, 2, 3) systems in the strongly correlated regime. We focus our attention on the responses of the N t o t = i n t e g e r states to an increasing magnetic field B, where N t o t is the total charge number on the dots. We show that when the charge level 𝜖 is chosen at the particle-hole (p-h) symmetric case, spin filtering is difficult to occur. While if 𝜖 is beyond the p-h symmetric point, perfect spin-polarized currents could be achieved, and the spin directions can be easily manipulated by tuning external electric and/or magnetic fields, making it easy to be realized in future experiments of the ideas. To approach these problems, the celebrated numerical renormalization group (NRG) technique is implemented, the dynamical properties and the quantum fluctuations are shown.
KeywordsSpin filter Quantum dot system Numerical renormalization group Strongly correlated effect
We acknowledge financially the support from NSFC (no. 11504102), the Natural Science Foundation of Hubei Province (no. 2015CFC789), the Major Scientific Research Project Pre-funds (no. 2014XY06), and the Doctoral Scientific Research Foundation of HUAT (no. BK201407).