Effect of SpinOrbit Interaction and InPlane Magnetic Field on the Conductance of a Quasi.pdf

ArXiv : cond-mat/0311143 6 November 2003 Effect of Spin-Orbit Interaction and In-Plane Magnetic Field on the Conductance of a Quasi-One-Dimensional System Yuriy V. Pershin, James A. Nesteroff, and Vladimir Privman Center for Quantum Device Technology, Department of Physics and Department of Electrical and Computer Engineering, Clarkson University, Potsdam, New York 13699-5721, USA We study the effect of spin-orbit interaction and in-plane effective magnetic field on the conductance of a quasi-one-dimensional ballistic electron system. The effective magnetic field includes the externally applied field, as well as the field due to polarized nuclear spins. The interplay of the spin-orbit interaction with effective magnetic field significantly modifies the band structure, producing additional sub-band extrema and energy gaps, introducing the dependence of the sub-band energies on the field direction. We generalize the Landauer formula at finite temperatures to incorporate these special features of the dispersion relation. The obtained formula describes the conductance of a ballistic conductor with an arbitrary dispersion relation. Recently, there have been numerous studies, both theoretical and experimental, of the properties of quasi-one-dimensional systems [1-8]. The motivation behind this interest has been the observation of conductance quantization. Most quasi-one-dimensional systems, or Quantum Wires (QW), are created by a split gate technique in a two-dimensional electron gas (2DEG) [6,7]. When a negative potential is applied to the gates, the electrons are depleted underneath.