About the Authors

Robert Schulz, Ulrich Kleinekathöfer
School of Engineering and Science, Jacobs University Bremen, Bremen, Germany

Attilio V. Vargiu, Francesca Collu, Paolo Ruggerone
Istituto Officina dei Materiali del CNR, UOS SLACS and Dipartimento di Fisica, Universita' degli Studi di Cagliari, Monserrato, Italy

Corresponding Author

vargiu@dsf.unica.it

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: RS AVV UK PR. Performed the experiments: RS AVV FC. Analyzed the data: RS AVV UK PR. Contributed reagents/materials/analysis tools: RS AVV. Wrote the paper: RS AVV UK PR. Contributed materials: FC.