1. Department of Physics, Gothenburg University, SE-412 96 Göteborg, Sweden
2. Energy Conversion, Research Institutes of Sweden, SE-504 62, Borås, Sweden
3. Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
4. ALISTORE-European Research Institute, CNRS FR 3104, Hub de l’Energie, Rue Baudelocque, 80039 Amiens Cedex, France