Hyperfine Stark effect of shallow donors in silicon
Hyperfine Stark effect of shallow donors in silicon
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DOI：
10.1103/physrevb.90.195204
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发表时间：
2014-11-18
影响因子：
3.7
通讯作者：
Lovett, Brendon W.
中科院分区：
文献类型：
--
作者：
Pica, Giuseppe;Wolfowicz, Gary;Lovett, Brendon W.
我们给出了体相掺杂硅中斯塔克效应的完整的理论处理，其预测得到了实验测量的支持。多谷有效质量理论，非微扰地处理由施主相关的中央胞势引起的谷-轨道相互作用，使我们能够在一个相对简单的框架内得到非常可靠的施主波函数的图像。在具有两个拟合势的赝势中，用新的试探波函数计算的1s施主结合能的变分最优化，使得实验确定的施主能级精确匹配，同时通过对施主核和电子自旋之间的接触超精细耦合的拟合，捕捉到了电子密度的正确的极限行为，无论是靠近还是远离每个杂质核。为了模拟斯塔克物理，我们进一步引入了一个外部均匀电场：在没有额外特殊参数的情况下，完全施主基态能量的变分最小化允许定量描述场诱导的每个杂质核电子密度的降低。接触超精细耦合的位移与实验值的详细比较表明，所有被测量的施主(P、As、Sb和Bi)都非常接近。最后，我们估计了施主基态的场电离阈值，从而为类凯恩结构中单量子比特操作的门操作时间设置了上限：Si：BI系统允许A门的速度高达10 MHz。
We present a complete theoretical treatment of Stark effects in bulk doped silicon, whose predictions are supported by experimental measurements. A multivalley effective mass theory, dealing nonperturbatively with valley-orbit interactions induced by a donor-dependent central cell potential, allows us to obtain a very reliable picture of the donor wave function within a relatively simple framework. Variational optimization of the 1s donor binding energies calculated with a new trial wave function, in a pseudopotential with two fitting parameters, allows an accurate match of the experimentally determined donor energy levels, while the correct limiting behavior for the electronic density, both close to and far from each impurity nucleus, is captured by fitting the measured contact hyperfine coupling between the donor nuclear and electron spin. We go on to include an external uniform electric field in order to model Stark physics: with no extra ad hoc parameters, variational minimization of the complete donor ground energy allows a quantitative description of the field-induced reduction of electronic density at each impurity nucleus. Detailed comparisons with experimental values for the shifts of the contact hyperfine coupling reveal very close agreement for all the donors measured (P, As, Sb, and Bi). Finally, we estimate field ionization thresholds for the donor ground states, thus setting upper limits to the gate manipulation times for single qubit operations in Kane-like architectures: the Si: Bi system is shown to allow for A gates as fast as approximate to 10 MHz.