1. Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), 7034, Trondheim, Norway
2. Experimental Physics V, University of Augsburg, 86159, Augsburg, Germany
3. Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
4. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. Department of Physics, ETH Zurich, 8093, Zurich, Switzerland