Nature Communications 4: Article number: 1536 10.1038/ncomms2546 (2013); Published: February262013; Updated: October172013.
The funding for this Article was not fully acknowledged. The Acknowledgements should have read:
This work was funded by DOE, Office of Basics Energy Sciences through DE SC 0004889, and by the National Science Foundation through MRSEC DMR-1119826. We thank Sindee Simon and Dan Miracle for useful discussions.
