Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 32: 2D Materials I: Structure and Electronic Properties
O 32.4: Vortrag
Dienstag, 8. März 2016, 11:15–11:30, H24
Absence of Dirac cones in monolayer silicene and multilayer Si films on Ag(111) — •Paolo Moras1, Sanjoy K. Mahatha1, Polina M. Sheverdyaeva1, Valerio Bellini1,2, Claudia Struzzi3, Luca Petaccia3, Tevfik O. Mentes3, Andrea Locatelli3, Roberto Flammini4, Karsten Horn5, and Carlo Carbone1 — 1Istituto di Struttura della Materia - CNR, Trieste, Italy — 2Istituto di Nanoscienze - CNR, Modena, Italy — 3Elettra Sincrotrone Trieste, Trieste, Italy — 4Istituto di Struttura della Materia - CNR, Roma, Italy — 5Fritz Haber Institute of the Max Planck Society, Berlin, Germany
Monolayer silicene and multilayer silicon films on Ag(111) have been subject of many investigations within the last few years. For both systems, photoemission data have been interpreted in terms of linearly dispersing bands giving rise to the characteristic *Dirac cone* feature in the valence band. Here we show, on the basis of angle-resolved photoemission data and ab-initio calculations [1,2] that this assignment is not correct. In monolayer silicene the *Dirac cone* feature is caused by an Ag-derived interface state, while multilayer Si films exhibit a clear diamond-like structure and bulk-like Si bands. These results question the validity of the claim that graphene-like 2-D silicon and silicene multilayers are in fact formed on Ag(111).
[1] P. Moras et al., J. Phys.: Condens. Matter 26, 185001 (2014).
[2] S. K. Mahatha et al., Phys. Rev. B 89, 201416(R) (2014).