1. Department of Physics, Stanford University, Stanford, California 94305, United States
2. Stanford Institute for Materials & Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
3. Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
4. SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
5. Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
6. Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, California 94305, United States