Modulated Rashba interaction in a quantum wire: Spin and charge dynamics

935 7 4018 1 11154 document 4018 2011_PRB_84_075466.pdf application/pdf ea2fca4d43ddbc066956bf49fb6f9f3f MD5 1043133 2014-02-08 15:24:42 http://eprints.iliauni.edu.ge/935/1/2011_PRB_84_075466.pdf 935 1 1 application/pdf text ge public

2011_PRB_84_075466.pdf

4026 2 11168 document 4026 lightbox.jpg image/png 3866468b0bf617afc072b191ab6f7532 MD5 56567 2014-02-08 15:44:46 http://eprints.iliauni.edu.ge/935/3/lightbox.jpg 935 3 3 image/png other Thumbnails conversion from text to thumbnail_lightbox ge public

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http://eprints.org/relation/isVersionOf http://eprints.iliauni.edu.ge/id/document/4018 http://eprints.org/relation/isVolatileVersionOf http://eprints.iliauni.edu.ge/id/document/4018 http://eprints.org/relation/issmallThumbnailVersionOf http://eprints.iliauni.edu.ge/id/document/4018 archive 34 disk0/00/00/09/35 2014-02-09 11:57:01 2015-04-03 06:13:02 2014-02-09 11:57:01 article show Malard Mariana Japaridze G.I. gia_japaridze@iliauni.edu.ge Johannesson Henrik Modulated Rashba interaction in a quantum wire: Spin and charge dynamics pub QC fac_eng public It was recently shown that a spatially modulated Rashba spin-orbit coupling in a quantum wire drives a transition from a metallic to an insulating state when the wave number of the modulation becomes commensurate with the Fermi wave length of the electrons in the wire [G. I. Japaridze et al., Phys. Rev. B v.80 041308(R) (2009)]. On basis of experimental data from a gated InAs heterostructure it was suggested that the effect may be put to practical use in a future spin transistor design. In the present article we revisit the problem and present a detailed analysis of the underlying physics. First, we explore how the build-up of charge density wave correlations in the quantum wire due to the periodic gate configuration that produces the Rashba modulation influences the transition to the insulating state. The interplay between the modulations of the charge density and that of the spin-orbit coupling turns out to be quite subtle: Depending on the relative phase between the two modulations, the charge-density wave correlations may either enhance or reduce the Rashba current blockade effect. Secondly, we inquire about the role of the Dresselhaus spin-orbit coupling that is generically present in a quantum wire embedded in semiconductor heterostructure. While the Dresselhaus coupling is found to work against the current blockade of the insulating state, the effect is small in most materials. Using an effective field theory approach, we also carry out an analysis of effects from electron-electron interactions, and show how the single-particle gap in the insulating state can be extracted from the more easily accessible collective charge and spin excitation thresholds. The smallness of the single-particle gap together with the anti-phase relation between the Rashba and chemical potential modulations pose serious difficulties for realizing a Rashba-controlled current switch in an InAs-based device. Some alternative designs are discussed. 2011-07-29 submitted Physical Review B 84 7 American Physical Society 075466-1 TRUE