[1] Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA
[2] Harvard Univ, Dept Phys, Cambridge, MA 02138 USA
[3] Northeastern Univ, Dept Phys, Boston, MA 02115 USA
[4] Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA
[5] Ames Natl Lab, Ames, IA 50011 USA
[6] MIT, Dept Phys, Cambridge, MA 02139 USA
[7] Univ Calif Los Angeles, Dept Phys & Astron & Calif NanoSyst Inst, Los Angeles, CA 90095 USA
[8] Natl Cheng Kung Univ, Dept Phys, Tainan 701, Taiwan
[9] Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA
[10] Boston Coll, Dept Phys, Chestnut Hill, MA USA
[11] Tata Inst Fundamental Res, Dept Condensed Matter Phys & Mat Sci, Mumbai, India
[12] Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton, I-1 Namiki, Tsukuba 3050044, Japan
[13] Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Cambridge, MA 02138 USA
[14] Harvard Univ, Ctr Nanoscale Syst, Cambridge, MA 02138 USA
[15] Acad Sinica, Inst Phys, Taipei 11529, Taiwan
[16] Ctr Quantum Frontiers Res & Technol QFort, Tainan 701, Taiwan
[17] Phys Div Natl Ctr Theoret Sci, Taipei 10617, Taiwan
[18] Canadian Inst Adv Res, Toronto, ON, Canada