1. Data
Storage Systems Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
2. Department
of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
3. Sun Yat-sen University−Carnegie
Mellon University Joint Institute of Engineering, Sun Yat-sen University, Guangzhou, China
4. Sun Yat-sen University−Carnegie
Mellon University Shunde International Joint Research Institute, Sun Yat-sen University, Guangdong, China
5. Department
of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States