tailieunhanh - Báo cáo hóa học: "Double Rashba Quantum Dots Ring as a Spin Filte"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Double Rashba Quantum Dots Ring as a Spin Filteb | Nanoscale Res Lett 2008 3 343-347 DOI s11671-008-9163-z NANO IDEAS Double Rashba Quantum Dots Ring as a Spin Filter Feng Chi Xiqiu Yuan Jun Zheng Received 11 August 2008 Accepted 21 August 2008 Published online 3 September 2008 to the authors 2008 Abstract We theoretically propose a double quantum dots QDs ring to filter the electron spin that works due to the Rashba spin-orbit interaction RSOI existing inside the QDs the spin-dependent inter-dot tunneling coupling and the magnetic flux penetrating through the ring. By varying the RSOI-induced phase factor the magnetic flux and the strength of the spin-dependent inter-dot tunneling coupling which arises from a constant magnetic field applied on the tunneling junction between the QDs a 100 spin-polarized conductance can be obtained. We show that both the spin orientations and the magnitude of it can be controlled by adjusting the above-mentioned parameters. The spin filtering effect is robust even in the presence of strong intra-dot Coulomb interactions and arbitrary dot-lead coupling configurations. Keywords Quantum dots Spin filter Rashba spin-orbit interaction Spin-dependent inter-dot coupling Introduction With the rapid progress in miniaturization of the solid-state devices the effect of carriers spin in semiconductor has attracted considerable attention for its potential applications in photoelectric devices and quantum computing 1 2 . The traditional standard method of spin control depends on the spin injection technique with mainly relies on optical techniques and the usage of a magnetic field or F. Chi El X. Yuan J. Zheng Department of Physics Bohai University Jinzhou 121000 People s Republic of China e-mail chifeng@ ferromagnetic material. Due to its unsatisfactory efficiency in nano-scale structures 1 3 4 generating and controlling a spin-polarized current with all-electrical means in mesoscopic structures has been an actively researched topic in recent years. The electric field usually .