Kinetic magnetoelectric effect in a 2D semiconductor strip due to boundary-confinement indu.pdf

a r X i v : c o n d - m a t / 0 6 0 3 7 5 5 v 1 [ c o n d - m a t .m e s - h a l l ] 2 8 M a r 2 0 0 6 Kinetic magnetoelectric effect in a 2D semiconductor strip due to boundary-confinement induced spin-orbit coupling Yongjin Jiang1 and Liangbin Hu2 1Department of physics, Zhejiang Normal University, Jinhua, Zhejiang 321004, P. R. China 2Department of physics and Laboratory of photonic information technology, South China Normal University, Guangdong 510631, P. R. China In a thin strip of a two-dimensional semiconductor electronic system, spin-orbit coupling may be induced near both edges of the strip due to the substantial spatial variation of the confining potential in the boundary regions. In this paper we show that, in the presence of boundary-confinement induced spin-orbit coupling, a longitudinal charge current circulating through a 2D semiconductor strip may cause strong non-equilibrium spin accumulation near both edges of the strip. The spins will be polarized along the normal of the 2DEG plane but in opposite directions at both edges of the strip. This phenomenon is essentially a kinetic magnetoelectric effect from the theoretical points of view, but it manifests in a very similar form as was conceived in a spin Hall effect. PACS numbers: 72.25.-b, 75.47.-m I. INTRODUCTION There has recently been much interest in a fascinating topic in the research community, namely spin Hall effect ( SHE ). SHE is such a phenomenon that a transverse spin current is generated when a longitudinal charge cur- rent circulates through a sample, and if the sample has a thin strip geometry, the transverse spin current will cause non-equilibrium spin accumulation at both edges of the sample1,2,3. Such a phenomenon would be much useful in the context of semiconductor spin-based electronics ( spintronics ) because it might provide an effective way for generating spin currents and/or non-equilibrium spin density in a nonmagnetic semiconductors without use of ferromagnetic meta