1. Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
2. Institut für Theorie der Statistischen Physik, RWTH Aachen University and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
3. Department of Physics, Columbia University, New York, New York 10027, United States
4. National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan