About the Authors

Samia Dhahri

Affiliation Géosciences Montpellier, University Montpellier 2, CNRS, Montpellier, France

Michel Ramonda

Affiliation Centrale de Technologie en Micro et nanoélectronique, Laboratoire de Microscopie en Champ Proche, University Montpellier 2, Montpellier, France

Christian Marlière

christian.marliere@u-psud.fr

Affiliations Géosciences Montpellier, University Montpellier 2, CNRS, Montpellier, France, Institut des Sciences Moléculaires d'Orsay, University Paris-Sud, CNRS, Orsay, France

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: CM. Performed the experiments: SD CM MR. Analyzed the data: SD CM. Contributed reagents/materials/analysis tools: CM. Wrote the paper: SD CM.