Department of Physics, The University of Texas at Austin, Austin, Texas 78712, and Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 Article Views are the COUNTER-compliant ...

† Kamerlingh Onnes Laboratorium, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands ‡ Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 Ga Delft, The ...