Issue
EPL
Volume 84, Number 6, December 2008
Article Number 67012
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/84/67012
Published online 12 January 2009
EPL, 84 (2008) 67012
DOI: 10.1209/0295-5075/84/67012

Transmission phase and spin filter effect in a four-terminal interferometer

Yibo Ying, Guojun Jin and Yu-qiang Ma

National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University Nanjing, 210093, China

gjin@nju.edu.cn

received 2 October 2008; accepted in final form 13 November 2008; published December 2008
published online 12 January 2009

Abstract
We study the transmission phase and spin-dependent magnetoconductance in a four-terminal Aharonov-Bohm ring with two embedded quantum dots. It is shown that the flux difference between the electron paths corresponding to different dot levels strongly modifies the measured transmission phase and Fano line shapes. The abrupt phase shift of $\pi $ between levels softens at high magnetic field and the Fano lines for the adjacent levels of a quantum dot exhibit opposite directions of asymmetric tail. The Fano line shapes of two spin components in conductance spectra can be tuned with the help of the Rashba spin-orbit coupling strength, dot level and structural configuration, and might provide practical applications in spintronic devices. It is interesting to find that our multi-terminal device acts as a good spin filter with one of its outgoing terminals up-polarized and one down-polarized.

PACS
73.23.-b - Electronic transport in mesoscopic systems.
85.35.Ds - Quantum interference devices.
73.21.La - Quantum dots.

© EPLA 2008