Magnetic Field Effects on Quantum-Dot Spin Valves

• Published in: Communications in theoretical physics Vol. 51; no. 3; pp. 555 - 562
• Main Author: GAO Jin-Hua SUN Qing-Feng XIE Xin-Cheng
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.03.2009
• Subjects: 塞曼分裂; 广义主方程; 形式主义; 磁场效应; 自旋极化; 自旋阀; 负微分电导; 量子点
• ISSN: 0253-6102
• DOI: 10.1088/0253-6102/51/3/35

We study the magnetic field effects on the spin-polarized transport of the quantum dot （QD） spin valve in the sequential tunneling regime. A set of generalized master equation is derived. Based on that, we discuss the collinear and noncollinear magnetic field effects, respectively. In the collinear magnetic field case, we find that the Zeeman splitting can induce a negative differential conductance （NDC）, which is quite different from the one found in previous studies. It has a critical polarization in the parallel arrangement and will disappear in the antiparallel configuration. In the noncollinear magnetic field case, the current shows two plateaus and their angular dependence is analyzed. Although sometimes the two current plateaus have similar angular dependence, their mechanisms are different. Our formalism is also suitable for calculating the transport in magnetic molecules, in which the spin splitting is induced not by a magnetic field but by the intrinsic magnetization.