Imaging the Acceptor Wave Function Anisotropy in Silicon.

Siegl, Manuel; Zanon, Julian; Sink, Joseph; Rodrigues da Cruz, Adonai; Hedgeland, Holly; Curson, Neil J; Flatté, Michael E; Schofield, Steven R · Nano Lett · 2025

basic_science · Level V

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Abstract

We present the first scanning tunneling microscopy (STM) image of hydrogenic acceptor wave functions in silicon. These acceptor states appear as square-ring-like features in STM images and originate from near-surface defects introduced by high-energy bismuth implantation into a silicon (001) wafer. Scanning tunneling spectroscopy confirms the formation of a p-type surface. Effective-mass and tight-binding calculations provide an excellent description of the observed square-ring-like features, confirming their acceptor character and attributing their symmetry to the light- and heavy-hole band degeneracy in silicon. A detailed understanding of the energetic and spatial properties of acceptor wave functions in silicon is essential for engineering large-scale acceptor-based quantum devices.