1. Materials Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
2. Metallurgical and Materials Engineering Department, Colorado School of Mines, Golden, Colorado 80401, United States
3. Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, United States
4. SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
5. Department of Mechanical Engineering, Stanford University, Palo Alto, California 94305, United States
6. Department of Physics, Colorado School of Mines, Golden, Colorado 80401, United States