The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform

E. L. Ivchenko - One of the best experts on this subject based on the ideXlab platform.

  • Spin splitting in symmetrical SiGe quantum wells
    Physical Review B, 2004
    Co-Authors: Leonid Golub, E. L. Ivchenko
    Abstract:

    Spin splitting of conduction electron states has been analyzed for all possible point symmetries of SiGe quantum well structures. A particular attention is paid to removal of Spin Degeneracy caused by the rotoinversion asymmetry of a (001) heterointerface between two diamond-lattice materials. The asymmetry is shown to result in Spin splitting of both Rashba and Dresselhaus types in symmetrical SiGe quantum wells. Consequences of the Spin splitting on Spin relaxation are discussed.

  • Interface-Induced Electron Spin Splitting in SiGe Heterostructures
    arXiv: Mesoscale and Nanoscale Physics, 2003
    Co-Authors: L. E. Golub, E. L. Ivchenko
    Abstract:

    Spin splitting of conduction electron states has been analyzed for all possible point symmetries of SiGe quantum well structures. A particular attention is paid to removal of Spin Degeneracy caused by the rotoinversion asymmetry of a (001) heterointerface between two diamond-lattice materials. Consequences of the Spin splitting on the electron Spin relaxation time is discussed.

  • Removal of Spin Degeneracy in p-SiGe quantum wells demonstrated by Spin photocurrents
    Physical Review B, 2002
    Co-Authors: Sergey Ganichev, Ulrich Rössler, Wilhelm Prettl, Vassilij Belkov, Richard Neumann, Karl Brunner, E. L. Ivchenko, Gerhard Abstreiter
    Abstract:

    Spin photocurrents requiring a system lacking inversion symmetry, become possible in SiGe based quantum well (QW) structures due to their built-in asymmetry. We report on circular and linear photogalvanic effects induced by infrared radiation in (001)- and (113)-oriented p-Si/Si1–xGex QW structures and analyze the observations in view of the possible symmetry of these structures. The circular photogalvanic effect arises due to optical Spin orientation of free carriers in QW's with Spin-split subbands. It results in a directed motion of free carriers in the plane of the QW. We discuss possible microscopic mechanisms that could remove the Spin Degeneracy of the electronic subband states.

Sergey Ganichev - One of the best experts on this subject based on the ideXlab platform.

  • Spin-GALVANIC EFFECT AND Spin ORIENTATION BY CURRENT IN NON-MAGNETIC SEMICONDUCTORS
    International Journal of Modern Physics B, 2008
    Co-Authors: Sergey Ganichev
    Abstract:

    The Spin-galvanic effect and the inverse effect, which yeilds current induced Spin polarization, in low dimensional semiconductor structures are reviewed. Both effect are caused by asymmetric Spin relaxation in systems with lifted Spin Degeneracy due to k-linear terms in the Hamiltonian.

  • Spin-Galvanic Effect in Quantum Wells
    arXiv: Condensed Matter, 2003
    Co-Authors: Sergey Ganichev, Eougenious Ivchenko, Vassilij Belkov, Sergey Tarasenko, M. Sollinger, D. Schowalter, Dieter Weiss, Werner Wegscheider, Wilhelm Prettl
    Abstract:

    It is shown that a homogeneous non-equlibrium Spin-polarization in semiconductor heterostructures results in an electric current. The microscopic origin of the effect is an inherent asymmetry of Spin-flip scattering in systems with lifted Spin Degeneracy caused by k-linear terms in the Hamiltonian.

  • Removal of Spin Degeneracy in p-SiGe quantum wells demonstrated by Spin photocurrents
    Physical Review B, 2002
    Co-Authors: Sergey Ganichev, Ulrich Rössler, Wilhelm Prettl, Vassilij Belkov, Richard Neumann, Karl Brunner, E. L. Ivchenko, Gerhard Abstreiter
    Abstract:

    Spin photocurrents requiring a system lacking inversion symmetry, become possible in SiGe based quantum well (QW) structures due to their built-in asymmetry. We report on circular and linear photogalvanic effects induced by infrared radiation in (001)- and (113)-oriented p-Si/Si1–xGex QW structures and analyze the observations in view of the possible symmetry of these structures. The circular photogalvanic effect arises due to optical Spin orientation of free carriers in QW's with Spin-split subbands. It results in a directed motion of free carriers in the plane of the QW. We discuss possible microscopic mechanisms that could remove the Spin Degeneracy of the electronic subband states.

  • Removal of Spin Degeneracy in SiGe based nanostructures
    2002
    Co-Authors: Sergey Ganichev, Ulrich Rössler, Wilhelm Prettl, Eougenious Ivchenko, Vassilij Belkov, Richard Neumann, Karl Brunner, Gerhard Abstreiter
    Abstract:

    The photogalvanic effects, which require a system lacking inversion symmetry, become possible in SiGe based quantum well (QW) structures due to their built-in asymmetry. We report on the removal of Spin Degeneracy in the k-space of SiGe nanostructures. This is concluded from the observations of the circular photogalvanic effect induced by infrared radiation in asymmetric p-type QWs. We discuss possible mechanisms that give rise to Spin-splitting of the electronic subband states.

  • Infrared radiation induced Spin photocurrents in GaN low-dimensional structures
    2005 Joint 30th International Conference on Infrared and Millimeter Waves and 13th International Conference on Terahertz Electronics, 1
    Co-Authors: W. Weber, Sergey Ganichev, Wilhelm Prettl, V. V. Bel'kov, Leonid Golub, Z. D. Kvon, Hyun-ick Cho, Jung-hee Lee
    Abstract:

    Infrared radiation Spin photocurrents have been observed in GaN quantum well structures. Observed currents change sign upon reversing of radiation helicity demonstrating an existence of Rashba/Dresselhaus Spin splitting of the conduction band in this new type of materials. Approvement of Spin Degeneracy removal in GaN structures allows to consider this material as a candidate for semiconductor Spintronic.

A.k. Schmid - One of the best experts on this subject based on the ideXlab platform.

  • Spin-induced forbidden evanescent states in III-V semiconductors
    Physical Review Letters, 2005
    Co-Authors: N. Rougemaille, H.j. Drouhin, S. Richard, G. Fishman, A.k. Schmid
    Abstract:

    Within the band gap of a semiconductor no electronic propagating states are allowed, but there exist evanescent states which govern charge transport such as tunneling. In this Letter, we address the issue of their Spin dependence in III-V semiconductors. Taking into account the Spin-orbit interaction, we treat the problem using a k center dot p 14x14 Hamiltonian that we numerically compute for GaAs. Our results show that the removed Spin Degeneracy in the band gap can lead to giant energy splittings and induces forbidden zones in k space where evanescent states are suppressed

Ulrich Zülicke - One of the best experts on this subject based on the ideXlab platform.

  • Anisotropic Zeeman Splitting In Ballistic One‐Dimensional Hole Systems
    arXiv: Mesoscale and Nanoscale Physics, 2007
    Co-Authors: R Danneau, Ar Hamilton, David A. Ritchie, Oleh Klochan, W R Clarke, L H Ho, Adam P. Micolich, Michelle Y. Simmons, Michael Pepper, Ulrich Zülicke
    Abstract:

    We have studied the effect of an in‐plane magnetic field B on a one‐dimensional hole system in the ballistic regime created by surface gate confinement. We observed clearly the lifting of the Spin Degeneracy due to the Zeeman effect on the one dimensional subbands for B applied parallel to the channel. In contrast, no Zeeman splitting is detected for B applied perpendicular to the channel, revealing an extreme anisotropy of the effective Lande g‐factor g*. We demonstrate that this anisotropy is a direct consequence of the one‐dimensional confinement on a system with strong Spin‐orbit coupling.

  • zeeman splitting in ballistic hole quantum wires
    Physical Review Letters, 2006
    Co-Authors: R Danneau, Ar Hamilton, David A. Ritchie, Oleh Klochan, W R Clarke, L H Ho, Adam P. Micolich, Michelle Y. Simmons, Michael Pepper, Ulrich Zülicke
    Abstract:

    : We have studied the Zeeman splitting in ballistic hole quantum wires formed in a (311)A quantum well by surface gate confinement. Transport measurements clearly show lifting of the Spin Degeneracy and crossings of the subbands when an in-plane magnetic field B is applied parallel to the wire. When B is oriented perpendicular to the wire, no Spin splitting is discernible up to B = 8.8 T. The observed large Zeeman splitting anisotropy in our hole quantum wires demonstrates the importance of quantum confinement for Spin splitting in nanostructures with strong Spin-orbit coupling.

  • Filtering Spin with tunnel-coupled electron wave guides
    Physical Review B, 2002
    Co-Authors: Michele Governale, Ulrich Zülicke, Daniel Boese, C. Schroll
    Abstract:

    We show how momentum-resolved tunneling between parallel electron wave guides can be used to observe and exploit lifting of Spin Degeneracy due to Rashba Spin-orbit coupling. A device is proposed that achieves Spin filtering without using ferromagnets or the Zeeman effect.

N. Rougemaille1 H.-j. Drouhin2 S. Richard3 G. Fishman - One of the best experts on this subject based on the ideXlab platform.

  • Spin-Induced Forbidden Evanescent States in III-V Semiconductors
    Physical Review Letters, 2005
    Co-Authors: N. Rougemaille1 H.-j. Drouhin2 S. Richard3 G. Fishman
    Abstract:

    Within the band gap of a semiconductor no electronic propagating states are allowed, but there exist evanescent states which govern charge transport such as tunneling. In this Letter, we address the issue of their Spin dependence in III-V semiconductors. Taking into account the Spin-orbit interaction, we treat the problem using a k p 14 14 Hamiltonian that we numerically compute for GaAs. Our results show that the removed Spin Degeneracy in the band gap can lead to giant energy splittings and induces forbidden zones in k space where evanescent states are suppressed.