*
Corresponding authors
a
Laboratoire matériaux et phénomènes quantiques, Université Paris Diderot–CNRS, UMR 7162, Bâtiment Condorcet, case courrier 7021, 75205 Paris Cedex 13, France
b
National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
c
National Center for NanoScience and Technology, Beijing 100190, China
d
SuperSTEM Laboratory, STFC Daresbury Campus, Keckwick Lane, Daresbury, UK
e
School of Mechanical and Advanced Materials Engineering, UNIST (Ulsan National Institute of Science and Technology), Ulsan 689-798, Republic of Korea
E-mail:
zonghoon.lee@gmail.com
f
School of Electrical Engineering, University of Ulsan, NamGu, Ulsan 680-749, Republic of Korea
E-mail:
jewni58@gmail.com
Fax: +82-52-259-1402
Tel: +82-52-259-1402