title: Metallic nature of the alpha-Sn/Ge(111) surface down to 2.5 K.
abstract: Low temperature (down to 2.5 K) scanning tunneling microscopy (STM) and spectroscopy (STS) measurements are presented to assess the nature of the alpha-Sn/Ge(111) surface. Bias-dependent STM and STS measurements have been used to demonstrate that such a surface preserves a metallic 3 x 3 reconstruction at very low temperature. A tip-surface interaction mechanism becomes active below about 20 K at the alpha-Sn/Ge(111) surface, resulting in an apparent unbuckled (sqrt[3] x sqrt[3]) reconstruction when filled states STM images are acquired with tunneling currents higher than 0.2 nA.
authors.affiliation: ISM CNR, Via del Fosso del Cavaliere 100, I-00133 Roma, Italy. colonna@ism.cnr.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Colonna
authors.forename: Fabio
authors.initials: F
authors.lastname: Ronci
authors.forename: Antonio
authors.initials: A
authors.lastname: Cricenti
authors.forename: Guy
authors.initials: G
authors.lastname: Le Lay