Jin, Liang http://orcid.org/0000-0003-1898-6317
Pfender, Matthias http://orcid.org/0000-0003-3934-8306
Aslam, Nabeel
Neumann, Philipp http://orcid.org/0000-0003-2146-0412
Yang, Sen
Wrachtrup, Jörg
Liu, Ren-Bao http://orcid.org/0000-0002-0620-2370
Article History
Received: 27 November 2014
Accepted: 3 August 2015
First Online: 23 September 2015
Competing interests
: The authors declare no competing financial interests.