[1] Stanford Univ, Geballe Lab Adv Mat, Stanford, CA 94305 USA
[2] Stanford Inst Mat & Energy Sci, SLAC Natl Accelerator Lab, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA
[3] Stanford Univ, Stanford Nano Shared Facil, Stanford, CA 94305 USA
[4] Los Alamos Natl Lab, Los Alamos, NM 87545 USA
[5] Niigata Univ, Fac Engn, Ikarashi, Niigata 9502181, Japan
[6] Swiss Fed Inst Technol, Inst Theoret Phys, CH-8093 Zurich, Switzerland
[7] Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA