Metal-to-insulator transition in thin-film polymeric AC(60)

Autor(en)

Roberto Macovez, Michael R C Hunt, Junjun Shan, Andrea Goldoni, Thomas Pichler, Maddalena Pedio, Paolo Moras, Carla Castellarin-Cudia, Joachim Schiessling, Luc Venema, Petra Rudolf

Abstrakt

We present an electron spectroscopy study of phase-pure AC60 thin films (A= Rb, Cs) in their monomer (face-centred cubic (fcc)) and polymer phases. A surface electronic reconstruction is observed in polymeric RbC60, analogous to that reported for the fcc phase. As for pristine C60, the occupied electronic states of AC60 fullerides are not dramatically affected by polymerization. The energy separation between the leading feature in photoemission and inverse photoemission is similar in both stable AC60 phases. These observations suggest that electron correlation effects are similar in the two phases, and that their different electronic behaviour is mainly related to the reduction of degeneracy of the polymer frontier states. Photoemission and electron-energy loss spectroscopy data show that the thin-film form of the RbC60 polymer is metallic at room temperature, and that it undergoes a metal–insulator transition at around 100 K. This transition temperature is much higher than that reported for the corresponding bulk phase and signals a poorer screening of Coulomb interactions at the film surface.

Organisation(en)

Elektronische Materialeigenschaften

Externe Organisation(en)

University of Groningen, Durham University, Laboratorio TASC INFM-CNR, Elettra Sincrotrone Trieste, Uppsala University

Journal

New Journal of Physics

Band

11

Anzahl der Seiten

15

ISSN

1367-2630

DOI

https://doi.org/10.1088/1367-2630/11/2/023035

Publikationsdatum

2009

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/94bc90ae-b85b-4661-9bd6-73da67625cc1