1. Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
2. Materials Physics and Applications−11, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
3. Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California 92093, United States
4. Sharp Laboratories, Camas, Washington 98607, United States