IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Thursday Sessions
       Session SS2-ThM

Paper SS2-ThM6
Temperature-Dependent Fermi Gap Opening in the c(6X4)-C@sub 60@/Ag(100) Two-Dimensional Superstructure

Thursday, November 1, 2001, 10:00 am, Room 122

Session: Electronic Structure II
Presenter: M. Sancrotti, Laboratorio Nazionale TASC-INFM, Italy
Authors: M. Sancrotti, Laboratorio Nazionale TASC-INFM, Italy
C. Cepek, Laboratorio Nazionale TASC-INFM, Italy
I. Vobornik, Laboratorio Nazionale TASC-INFM, Italy
A. Goldoni, Sincrotrone Trieste, Italy
E. Magnano, Laboratorio Nazionale TASC-INFM, Italy
G. Selvaggi, Universita' di Modena, Italy
J. Kröger, Zürich Universität, Switzerland
G. Panaccione, Laboratorio Nazionale TASC-INFM, Italy
G. Rossi, Laboratorio Nazionale TASC-INFM, Italy
Correspondent: Click to Email
The interest in fullerene-based films, their surfaces, and related low-dimensional systems has been recently renewed for example by the discovery that superconductivity persists at surfaces of A@sub 3@C@sub 60@ films@footnote 1@ and by the possibility of achieving a critical temperature as high as 52 K in hole-doped C@sub 60@ single crystals.@footnote 2@ The possibility of controlling at a fine scale the charge state of single C@sub 60@ molecules and the buckyball-buckyball distance makes the fullerene-based films extremely charming for a wide range of applications. In addition, chemical and physical properties of low-dimensional C@sub 60@-based layers may be considered superior to the bulk materials, prepared by means of standard intercalation methods and plagued by the presence of multi-phases. Here we report on a high-resolution angle integrated photoemission study@footnote 3@ of one monolayer of C@sub 60@ chemisorbed on Ag(100). The results show the reversible opening of a gap at the Fermi level at temperatures 25 @<=@ T @<=@ 300 K. The gap reaches a maximum value of 10 meV at T @<=@ 70 K. This finding is a first evidence of an electronic phase transition in C@sub 60@ monolayers and has implications on the ongoing debate about surface superconductivity in C@sub 60@-based bulk materials. @FootnoteText@ @footnote 1@ R. Hesper, L.H. Tjeng, A. Heeres, and G.A. Sawatzky, Phys. Rev. Lett. 85 (2000) 1970 @footnote 2@ J.H. Schön, Ch. Kloc, R.C. Haddon, and B. Batlogg, Science 288 (2000) 656 @footnote 3@ C. Cepek, I. Vobornik, A. Goldoni, E. Magnano, G. Selvaggi, J. Kröger, G. Panaccione, G. Rossi, and M. Sancrotti, Phys. Rev. Lett. 86 (2001) 3100