1. Department of Applied Physics, Stanford University, Stanford, CA 93205, USA.
2. Department of Mechanical Engineering, Stanford University, Stanford, CA 93205, USA.
3. SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
4. SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
5. Department of Material Science and Engineering, Stanford University, Stanford, CA 94305, USA.
6. Department of Physics, Stanford University, Stanford, CA 94305, USA.
7. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.