  The precise positioning of dopant atoms within bulk crystal lattices could
enable novel applications in areas including solid-state sensing and quantum
computation. Established scanning probe techniques are capable tools for the
manipulation of surface atoms, but at a disadvantage due to their need to bring
a physical tip into contact with the sample. This has prompted interest in
electron-beam techniques, followed by the first proof-of-principle experiment
of bismuth dopant manipulation in crystalline silicon. Here, we use first
principles modeling to discover a novel indirect exchange mechanism that allows
electron impacts to non-destructively move dopants with atomic precision within
the silicon lattice. However, this mechanism only works for the two heaviest
group V donors with split-vacancy configurations, Bi and Sb. We verify our
model by directly imaging these configurations for Bi, and by demonstrating
that the promising nuclear spin qubit Sb can be manipulated using a focused
electron beam.
