1. Department of Physics, Scottish Universities Physics Alliance (SUPA), University of Strathclyde, Glasgow G4 0NG, United Kingdom
2. Department of Electrical & Electronic Engineering, University of Bath, Bath BA2 7AY, United Kingdom
3. Centre de Recherche sur l’Hétéro-Epitaxie et ses Applications (CRHEA)−Centre National de la Recherche Scientifique (CNRS), Rue Bernard Grégory, 06560 Valbonne, France
4. Department of Materials Science and Metallurgy, University of Cambridge, CB3 OFS Cambridge, United Kingdom
5. Institute of Solid State Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany