1. Donostia International Physics Center, E-20018 San Sebastián, Spain
2. Ikerbasque, Basque Foundation for Science, E-48011 Bilbao, Spain
3. Nano-Bio
Spectroscopy Group and ETSF, Universidad del País Vasco, CFM CSIC-UPV/EHU-MPC, 20018 San Sebastián, Spain
4. Department
of Physics, University of California, Berkeley, California 94720, United States
5. Department
of Chemistry, University of California, Berkeley, California 94720, United States
6. Materials
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
7. Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
8. Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
9. Center for Free-electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany