arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0709.0268cond-mat.mtrl-sci
收藏

半导体中深施主间的交换:量子亏损方法

Exchange between deep donors in semiconductors: a quantum defect approach

W. Wu, A. J. Fisher

摘要:

半导体中缺陷之间的交换相互作用通常在有效质量理论中使用标度类氢波函数来处理。然而,这样的波函数只适用于浅杂质,在这里,我们提出了一个简单但强大的概括治疗深施主,在其中,我们使用完善的量子亏损理论治疗的波函数的长程部分,并包括一个模型中心单元校正固定在实验观察值的束缚态本征值。这使我们能够计算结合能对交换相互作用的影响,作为供体距离的函数;这是一个重要的数量,给出了最近的建议,进行量子信息处理使用深供体。正如预期的那样,交换相互作用被抑制(或增加),相比类氢的情况下,更大的本地化(或离域)的波函数的深捐助者(或“超浅”捐助者的结合能小于类氢值)。计算结果进行了比较与一个简单的缩放海特勒-伦敦类氢交换;缩放类氢结果给出正确的数量级,但未能定量再现我们的计算。我们计算了硅中的施主交换,包括沿$\{100\}$方向的施主对的谷间干扰项,并且还显示了施主类型对不同浓度下最近邻交换常数分布的影响。我们的方法可以用来计算任意结合能的两个施主电子之间的交换相互作用。

英文摘要:

Exchange interactions among defects in semiconductors are commonly treated within effective-mass theory using a scaled hydrogenic wave-function. However such a wave-function is only applicable to shallow impurities; here we present a simple but robust generalization to treat deep donors, in which we treat the long-range part of the wavefunction using the well established quantum defect theory, and include a model central-cell correction to fix the bound-state eigenvalue at the experimentally observed value. This allows us to compute the effect of binding energy on exchange interactions as a function of donor distance; this is a significant quantity given recent proposals to carry out quantum information processing using deep donors. As expected, exchange interactions are suppressed (or increased), compared to the hydrogenic case, by the greater localization (or delocalization) of the wavefunctions of deep donors (or `super-shallow' donors with binding energy less then the hydrogenic value). The calculated results are compared with a simple scaling of the Heitler-London hydrogenic exchange; the scaled hydrogenic results give the correct order of magnitude but fail to reproduce quantitatively our calculations. We calculate the donor exchange in silicon including inter-valley interference terms for donor pairs along the $\{100\}$ direction, and also show the influence of the donor type on the distribution of nearest-neighbour exchange constants at different concentrations. Our methods can be used to compute the exchange interactions between two donor electrons with arbitrary binding energy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑