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A spin dephasing mechanism mediated by the interplay between the spin-orbit coupling and the asymmetrical confining potential in semiconductor quantum dot

Research paper by Rui Li

Indexed on: 28 May '18Published on: 28 May '18Published in: arXiv - Physics - Mesoscopic Systems and Quantum Hall Effect



Abstract

Understanding the spin dephasing mechanism is of fundamental importance in all potential applications of the spin qubit. Here we demonstrate a spin dephasing mechanism in semiconductor quantum dot due to the $1/f$ charge noise. The spin-charge interaction is mediated by the interplay between the spin-orbit coupling and the asymmetrical quantum dot confining potential. The dephasing rate is proportional to both the strength of the spin-orbit coupling and the degree of the asymmetry of the confining potential. The evaluated spin dephasing time is about ${\rm T}^{*}_{2}=7$ $\mu$s, $275$ $\mu$s, and $55$ ms in a InSb, InAs, and GaAs nanowire quantum dots with a moderate well-height $V_{0}=10$ meV. In particular, the spin dephasing can be enhanced by lowering the well-height. When the well-height is as small as $V_{0}=5$ meV, the spin depahsing time in InSb, InAs, and GaAs quantum dots is reduced to ${\rm T}^{*}_{2}=0.38$ $\mu$s, $18$ $\mu$s, and $9$ ms.