^aDepartment of Materials Science and Engineering, University of Illinois, 1304 W. Green Street, Urbana, IL 61801, USA,^bInstitute of Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly Thege M. u. 29–33, H-1121 Budapest, Hungary,^cIntel Corporation, Technology Manufacturing Group, 2501 NE Century Boulevard, Hillsboro, OR 97124, USA,^dUniversity of Ulm, Central Facility for Electron Microscopy, Electron Microscopy Group of Materials Science (EMMS), Albert Einstein Allee 11, 89069 Ulm, Germany, and ^eInstitut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, Welderweg 11, 55099 Mainz, Germany
Correspondence e-mail:  jianzuo@illinois.edu