1. Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China
2. Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 2835, Bremen, Germany
3. Department of Physical and Macromolecular Chemistry & Charles University Centre of Advanced Materials, Faculty of Science, Charles University in Prague, Hlavova 8, Prague 2, 128 43, Czech Republic