1. Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
2. Materials Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
3. Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14850, USA
4. Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
5. Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
6. Department of Applied Physics, Stanford University, Stanford, CA 94305, USA