Element-sensitive measurement of the hole-nuclear spin interaction in quantum dots
Element-sensitive measurement of the hole-nuclear spin interaction in quantum dots
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DOI：
10.1038/nphys2514
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发表时间：
2013-02-01
期刊：
影响因子：
19.6
通讯作者：
Tartakovskii, A. I.
中科院分区：
文献类型：
--
作者：
Chekhovich, E. A.;Glazov, M. M.;Tartakovskii, A. I.
有人提出，价带空穴可以形成稳健的自旋量子比特（1 - 4），因为它们的超精细耦合比电子（5，6）弱。然而，最近（7 - 11）表明空穴超精细相互作用是不可忽略的，尽管仍然缺乏控制其大小的机制的一致图片。在这里，我们解决这个问题，通过测量空穴超精细常数独立的每个化学元素在GaAs/GaAs，InP/GaInP和GaAs/AlGaAs量子点。与现有模型（10，11）相反，我们发现空穴超精细常数对于阳离子和阴离子具有相反的符号，并且相对于电子的空穴超精细常数在-15%到+15%的范围内。我们将这种变化归因于p-对称原子轨道的竞争性正贡献和d-轨道的负贡献。这些发现产生了关于价带轨道组成的信息（12），并为验证半导体纳米结构中计算的布洛赫波函数提供了一种全新的方法（13）。此外，我们发现，阳离子d轨道的贡献导致了一个新的机制的空穴自旋退相干。
It has been proposed that valence-band holes can form robust spin qubits(1-4) owing to their weaker hyperfine coupling compared with electrons(5,6). However, it was demonstrated recently(7-11) that the hole hyperfine interaction is not negligible, although a consistent picture of the mechanism controlling its magnitude is still lacking. Here we address this problem by measuring the hole hyperfine constant independently for each chemical element in In GaAs/GaAs, InP/GaInP and GaAs/AlGaAs quantum dots. Contrary to existing models(10,11) we find that the hole hyperfine constant has opposite signs for cations and anions and ranges from -15% to +15% relative to that for electrons. We attribute such changes to the competing positive contributions of p-symmetry atomic orbitals and the negative contributions of d-orbitals. These findings yield information on the orbital composition of the valence band(12) and enable a fundamentally new approach for verification of computed Bloch wavefunctions in semiconductor nanostructures(13). Furthermore, we show that the contribution of cationic d-orbitals leads to a new mechanism of hole spin decoherence.