Mending Cracks in Rutile TiO${}_2$ with Electron Beam

Restructuring of rutile TiO${}_2$ under electron beam irradiation driven by radiolysis was observed and analyzed using a combination of atomic-resolution imaging and electron energy loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM). It was determined that a high-energy (80-300 keV) electron beam at high doses ($⪆{10}^{7}e\mathrm{/}n{m}^2$) can constructively restructure rutile TiO${}_2$ with an efficiency of $6\times {10}^{-6}$. These observations were realized using rutile TiO${}_2$ samples with atomically sharp nanometer-wide cracks. Based on atomic-resolution STEM imaging and quantitative EELS analysis, we propose a $\mathrm{"}$ 2-step $\mathrm{"}$ rolling model of the octahedral building blocks of the crystal to account for observed radiolysis-driven atomic migration.