1. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
2. Department
of Materials Engineering, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
3. Geballe
Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, California 94305, United States
4. Photon Factory, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan
5. Department
of Applied Chemistry, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan