Nature Materials 14, 864–865 (2015); published online 3 August 2015; retracted after print 24 November 2016.

In view of the fact that the Article by P. Mahato et al. (Nature Materials 14, 924–930; 2015) has been retracted by the authors, we wish to retract this News & Views highlighting the study as it relied on the validity of the data presented therein.