Yang, Q. http://orcid.org/0000-0002-6203-7867
Su, Y. http://orcid.org/0000-0002-7042-0524
Chi, C.
Cherian, C. T.
Huang, K.
Kravets, V. G.
Wang, F. C. http://orcid.org/0000-0002-5954-3881
Zhang, J. C.
Pratt, A.
Grigorenko, A. N.
Guinea, F.
Geim, A. K.
Nair, R. R.
Article History
Received: 1 March 2017
Accepted: 5 October 2017
First Online: 13 November 2017
Competing interests
: The authors declare no competing financial interests.