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Spin Transport (spin + transport)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Tunneling current through g -factor engineered series quantum dots

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2009
Yasuhiro Tokura
Abstract We evaluate resonant tunneling current via series quantum dots with different g -factors by Bloch equation method. We found that the resonant current is always singly peaked as a function of bias and its peak position depends on the gate voltage. When the rate of spontaneous phonon emission is very small, the shift of the peak positions between single spin transport and both spin transport corresponds to the half of the difference of the Zeeman energy. In contrast, when the phonon assisted tunneling predominates, the peak always appears at one of the resonant tunneling conditions for larger bias. These features are explained by spin blockade effect. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Spin-Hall effect and spin coherent waves in semiconductors with Rashba spin-orbit interaction

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2008
P. Kleinert
Abstract Based on rigorous quantum-kinetic equations for the spin-density matrix, spin-charge coupled drift-diffusion equations are derived for a strongly confined twodimensional hole gas. An electric field leads to a coupling between the spin and charge degrees of freedom. For weak spin-orbit interaction, this coupling gives rise to the intrinsic spin-Hall effect that occurs in the diffusive regime. There exists a threshold value of the spin-orbit coupling constant that separates spin diffusion from ballistic spin transport. In the latter regime, undamped spin-coherent oscillations are observed. Their relationship to the zitterbewegung is discussed. The analytic results are compared with an exact microscopic approach valid in the ballistic regime. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Strong spin relaxation length dependence on electric field gradients

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2006
D. Csontos
Abstract We discuss the influence of electrical effects on spin transport, and in particular the propagation and relaxation of spin polarized electrons in the presence of inhomogeneous electric fields. We show that the spin relaxation length strongly depends on electric field gradients, and that significant suppression of electron spin polarization can occur as a result thereof. A discussion in terms of a drift-diffusion picture, and selfconsistent numerical calculations based on a Boltzmann-Poisson approach shows that the spin relaxation length in fact can be of the order of the charge screening length. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Coherent spin transport by acoustic fields in GaAs quantum wells

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2006
O. D. D. Couto
Abstract We review processes for long-range spin transport and manipulation in GaAs quantum wells using mobile potentials created by the piezoelectric field of a surface acoustic wave. By reducing spin dephasing mechanisms associated with the spin orbit-coupling, these potentials can coherently transport spins over distances on the order of 100 µm. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Proceedings of the 7th International Workshop on Nonlinear Optics and Excitation Kinetics in Semiconductors (NOEKS 7)

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2003
Martin Wegener
The 7th International Workshop on Nonlinear Optics and Excitation Kinetics in Semiconductors (NOEKS 7) was held at the Universität Karlsruhe (TH) from 24,28 February 2003. Topics of NOEKS 7 were: Ultrafast dynamics (coherent effects, coherent control, quantum kinetics, THz-experiments), photonic crystals (2D and 3D photonic band gap materials), quantum dot physics (quantum dots, quantum wires), spin effects (spin dephasing, spin transport), disorder-related effects, organic semiconductors, semiconductor quantum optics (luminescence, photon statistics), device physics (quantum cascade lasers, superlattices, interband lasers), and Bose-Einstein condensation of excitons. [source]

Quantum phase transition in a spin-½ XX chain with three-spin and uniform long-range interactions

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 15 2005
Ping Lou
Abstract A spin-½ XX chain with three-spin and uniform long-range interactions among the z components of the spins is constructed. Based upon the model, using the Jordan,Wigner transformation, the thermodynamic quantities and spin transports of the system are evaluated exactly. The phase diagram together with the key parameters characterizing quantum phase transitions is presented. It is noted that, similarly to classical first-order phase transitions, there are also the metastable states "supercooled" and "superheated" in the first-order quantum phase transitions. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]