Influence of temperature on the displacement threshold energy in graphene

Author(s)
Alexandru Ionut Chirita Mihaila, Toma Susi, Jani Kotakoski
Abstract

The atomic structure of nanomaterials is often studied using transmission electron microscopy. In addition to image formation, the energetic electrons impinging on the sample may also cause damage. In a good conductor such as graphene, the damage is limited to the knock-on process caused by elastic electron-nucleus scattering. This process is determined by the kinetic energy an atom needs to be sputtered, i.e. its displacement threshold energy Ed. This is typically assumed to have a fixed value for all electron impacts on equivalent atoms within a crystal. Here we show using density functional tight-binding simulations that the displacement threshold energy is affected by thermal perturbations of atoms from their equilibrium positions. This effect can be accounted for in the estimation of the displacement cross section by replacing the constant threshold energy value with a distribution. Our refined model better describes previous precision measurements of graphene knock-on damage, and should be considered also for other low-dimensional materials.

Organisation(s)
Physics of Nanostructured Materials
Journal
Scientific Reports
Volume
9
No. of pages
7
ISSN
2045-2322
DOI
https://doi.org/10.1038/s41598-019-49565-4
Publication date
09-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
103042 Electron microscopy, 103018 Materials physics
ASJC Scopus subject areas
General
Portal url
https://ucris.univie.ac.at/portal/en/publications/influence-of-temperature-on-the-displacement-threshold-energy-in-graphene(560b6f16-cf87-4dbc-a6f1-fd20cc7aeec3).html