1. Department of Applied Physics, Stanford University, Stanford, California 94305, United
States
2. Geballe Laboratory
for Advanced
Materials, Stanford University, Stanford,
California 94305, United States
3. Department of Physics, Stanford University, Stanford, California 94305, United
States
4. Stanford Institute for Materials
and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States