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