Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Parkville, 3010, VIC, Australia.
Nanoscale. 2017 Nov 9;9(43):17013-17019. doi: 10.1039/c7nr05081j.
Atomic-scale understanding of phosphorus donor wave functions underpins the design and optimisation of silicon based quantum devices. The accuracy of large-scale theoretical methods to compute donor wave functions is dependent on descriptions of central-cell corrections, which are empirically fitted to match experimental binding energies, or other quantities associated with the global properties of the wave function. Direct approaches to understanding such effects in donor wave functions are of great interest. Here, we apply a comprehensive atomistic theoretical framework to compute scanning tunnelling microscopy (STM) images of subsurface donor wave functions with two central-cell correction formalisms previously employed in the literature. The comparison between central-cell models based on real-space image features and the Fourier transform profiles indicates that the central-cell effects are visible in the simulated STM images up to ten monolayers below the silicon surface. Our study motivates a future experimental investigation of the central-cell effects via the STM imaging technique with potential of fine tuning theoretical models, which could play a vital role in the design of donor-based quantum systems in scalable quantum computer architectures.
对磷施主波函数的原子尺度理解是设计和优化基于硅的量子器件的基础。计算施主波函数的大规模理论方法的准确性取决于对中心胞修正的描述，这些修正通过经验拟合来匹配实验结合能或与波函数全局性质相关的其他量。理解施主波函数中这种效应的直接方法非常重要。在这里，我们应用了一种全面的原子理论框架，使用文献中先前使用的两种中心胞修正形式来计算亚表面施主波函数的扫描隧道显微镜（STM）图像。基于实空间图像特征和傅里叶变换轮廓的中心胞模型之间的比较表明，在距硅表面十个单层以下的位置，在模拟的 STM 图像中可以看到中心胞效应。我们的研究通过 STM 成像技术激发了对中心胞效应的未来实验研究，这种技术具有微调理论模型的潜力，这可能在可扩展量子计算机架构中基于施主的量子系统的设计中发挥重要作用。
