1. Nanoscience Centre, University of Cambridge, Cambridge CB3 0FF, United Kingdom, Semiconductor Research and Development Centre, Samsung Electronics Co., Yongin City, Korea, Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea, Department of Materials, Imperial College, Exhibition Road, London SW7 2AZ, United Kindom, and BK21 Physics Research Division, Department of Energy Science, Institute of Basic Science, SKKU Advanced Institute of Nanotechnology (SAINT) and...