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Ab Initio Structure Determination of Cu2–xTe Plasmonic Nanocrystals by Precession-Assisted Electron Diffraction Tomography and HAADF-STEM Imaging

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journal contribution
posted on 31.07.2018 by Enrico Mugnaioli, Mauro Gemmi, Renyong Tu, Jeremy David, Giovanni Bertoni, Roberto Gaspari, Luca De Trizio, Liberato Manna
We investigated pseudo-cubic Cu2–xTe nanosheets using electron diffraction tomography and high-resolution HAADF-STEM imaging. The structure of this metastable nanomaterial, which has a strong localized surface plasmon resonance in the near-infrared region, was determined ab initio by 3D electron diffraction data recorded in low-dose nanobeam precession mode, using a new generation background-free single-electron detector. The presence of two different, crystallographically defined modulations creates a 3D connected vacancy channel system, which may account for the strong plasmonic response of this material. Moreover, a pervasive rotational twinning is observed for nanosheets as thin as 40 nm, resulting in a tetragonal pseudo-symmetry.