Correction to: Scientific Reports https://doi.org/10.1038/s41598-018-30223-0, published online 24 August 2018

In the original version of this Article, N. De Leo and L. Boarino were incorrectly affiliated with ‘Institut de Ciència de Materials de Barcelona (ICMAB–CSIC), Campus de Bellaterra, 08193, Bellaterra, Spain’. The correct affiliation is listed below.

Nanofacility Piemonte INRiM, Nanoscience & Materials Division, Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135, Torino, Italy

This error has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Material.