Lozada-Hidalgo, Marcelo http://orcid.org/0000-0003-3216-7537
Zhang, Sheng http://orcid.org/0000-0001-7532-1923
Hu, Sheng
Kravets, Vasyl G.
Rodriguez, Francisco J. http://orcid.org/0000-0003-1213-0999
Berdyugin, Alexey
Grigorenko, Alexander
Geim, Andre K. http://orcid.org/0000-0003-2861-8331
Article History
Received: 16 June 2017
Accepted: 12 December 2017
First Online: 22 January 2018
Competing interests
: The authors declare no competing financial interests.