Scientific Reports 6: Article number: 23440; Published online: 22 March 2016; Updated: 29 April 2016

The Acknowledgements section in this Article was omitted. The Acknowledgements should read:

“We thank Dr. Kausik Chakraborty for thought provoking discussion. BSC0121 is duly acknowledged for providing support for this work. BLP acknowledges CSIR, India for providing fellowship.”