Marta Prada

Spin-Orbit Coupling (SOC) Parameters in Si/SiGe QWs: Structure (SIA) and Bulk (BIA) Inversion Asymmetry

Spin-Orbit Coupling (SOC) Parameters in Si/SiGe QWs: Structure (SIA) and Bulk (BIA) Inversion Asymmetry Clemens Heitzinger, Gerhard Klimeck

Objective:

  • Previous theoretical models for T2 do not agree with experimental results, as they ignore BIA effects
  • We want to determine the SIA alpha and BIA beta? coupling parameters

Approach:

  • Using NEMO-3D we compute the splitting of the lowest valleys due to SOC as a function of in-plane k
  • We get alpha and betaβ as a function of:
    • QW width, L
    • Electric field Ez

Impact

  • SOC determines T2 and T1, essential for quantum computation
  • Atomistic approach is essential for the interfaces: first time alpha and beta are computed using this method
  • Surprisingly alpha < beta
  • SOC has inter- and intra-valley contributions
  • alpha and beta are linear in k, Ez and are sample dependent
  • Two regimes as a function of Ez
    • Weak Field: alpha and beta decrease with L
    • Strong Field: alpha and beta are independent of L
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Marta Prada's Pages

Biography Si/InAs Composite Channels: Low Effective Mass and Direct Bandgap Structures Spin-Orbit Coupling (SOC) Parameters in Si/SiGe QWs: Structure (SIA) and Bulk (BIA) Inversion Asymmetry

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