1. Departament de Física, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, E-08193 Barcelona, Spain
2. Alba Synchrotron Light Facility, CELLS, Cerdanyola
del Vallès, E-08280 Barcelona, Spain
3. Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
4. Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, E-08193 Barcelona, Spain
5. ICREA, Pg. Lluís Companys 23, E-08010 Barcelona, Spain