2011/10/31 by Wayne M. Witzel, Wayne Witzel, Rajib Rahman +1 · 1 citation
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physrevb.85.205312
published as Phys. Rev. B 85, 205312 (2012)
openalex publication_date 2012/05/11 · arxiv created 2012/05/14 · arxiv updated 2012/05/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We theoretically study the nuclear spin induced decoherence of a quantum dot in Si that is confined at a SiGe interface. We calculate decoherence time dependence on 73Ge in the barrier layer to evaluate the importance of Ge as well as Si enrichment for long decoherence times. We use atomistic tight-binding modeling for an accurate account of the electron wave function which is particularly important for determining the contact hyperfine interactions with the Ge nuclear spins. We find decoherence times due to Ge spins at natural concentrations to be milliseconds. This suggests that SiGe/Si quantum dot devices employing enriched Si will require enriched Ge as well in order to benefit from long coherence times. We provide a comparison of T2 times for various fractions of nonzero spin isotopes of Si and Ge.