1. Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
2. Department of Science, University of Alberta, Camrose, Alberta T4V 2R3, Canada
3. Department of Physics and Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
4. IEK-13, Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany