[1] Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA
[2] Univ Calif San Diego, Ctr Adv Nanosci, La Jolla, CA 92093 USA
[3] Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA
[4] Univ Calif San Diego, Mat Sci & Engn Program, La Jolla, CA 92093 USA
[5] Univ Paris Saclay, Univ Paris Sud, CNRS, Unite Mixte Phys,Thales, F-91767 Palaiseau, France