1. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
2. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
3. Theory and Simulation of Condensed Matter, Department of Physics, King's College London, The Strand, London WC2R 2LS, United Kingdom
4. Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
5. Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
6. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
7. Department of Physics, University of California, Berkeley, California 94720, USA
8. NCEM, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA