Electron-beam manipulation of lattice impurities

Session

Stream 1: EMAG - 2D Materials

Authors

Ass.-Prof. Dr. Toma Susi (1)

Affiliations

1. University of Vienna

Keywords

scanning transmission electron microscopy, electron-beam manipulation, first principles modeling, heteroatoms, graphene, silicon

Abstract text

Covalently bound impurity atoms in crystal lattices can be manipulated using the atomically focused electron probe of an aberration-corrected scanning transmission electron microscope. This has revealed inspiring new perspectives for top-down atomic engineering, with the potential to surpass existing techniques in both versatility and capabilities.

Manipulation was first realized for incidental silicon impurities in single-layer graphene. Elastic backscattering of a probe electron from a moving C nucleus [1] causes the Si to directly exchange places with one neighboring C atom via an out-of-plane displacement [2], and such dynamics can be controlled by directing the focused electron beam at the desired atomic site [3]. Our manipulation rate is nearly on par with any atomically precise technique [4], and such control is also possible in single-walled carbon nanotubes [5].

Phosphorus dopants in graphene can be manipulated with difficulty [6], and there seem to be physical limits on what is feasible assignificantly heavier Ge impurities cannot [7]. The curious replacement of irradiated impurities by C atoms has also emerged as a practical hurdle for the further scaling of the technique. However, similar irradiation-induced atomic dynamics have been observed for many impurity elements [8], and based on our modeling, several transition metals also appear as promising targets.

Perhaps even more excitingly, the electron-beam manipulation of Bi dopants in bulk silicon was recently reported [9], although the precise mechanism was left unclear. We have now applied our established ab initio modeling methodology [10] to address this question, revealing a novel type of non-destructive mechanism we call indirect exchange. Further, we demonstrate that the promising nuclear spin qubit Sb can likewise be manipulated.

Support from the European Research Council (grant 756277-ATMEN) and computational resources provided by the Vienna Scientific Cluster (VSC) are gratefully acknowledged.

References

[1] T. Susi, J.C. Meyer, J. Kotakoski, Nat. Rev. Phys. 1, 397 (2019)
[2] T. Susi et al., Phys. Rev. Lett. 113, 115501 (2014)
[3] T. Susi et al., Ultramicroscopy 180, 163 (2017)
[4] M. Tripathi et al., Nano Lett. 18, 5319 (2018)
[5] K. Mustonen et al., Adv. Func. Mat. 29, 1901327 (2019)
[6] C. Su et al., Sci. Adv. 5:eaav2252 (2019)
[7] M. Tripathi et al., ACS Nano 12, 4641 (2018)
[8] T. Susi et al., 2D Mater. 4, 042004 (2017)
[9] B. Hudak et al., ACS Nano 12, 5873 (2018)
[10] T. Susi et al., Nature Commun. 7, 13040 (2016)