Institution: | aDepartment für Physik, Center for NanoScience, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany;bSchool of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK;cMaterials Department, University of California, Santa Barbara, CA 93106, USA |