1. Department of Engineering PhysicsÉcole Polytechnique de Montréal C. P. 6079, Succursale Centre‐Ville Montréal QC H3C 3A7 Canada
2. Center for the Physics of Materials and Department of PhysicsMcGill University Montréal QC H3A 2T8 Canada
3. Department of Materials Science and EngineeringCanadian Centre for Electron MicroscopyMcMaster University Hamilton ON L8S 4L7 Canada