Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: 2D Materials: Structure and Electronic Properties
(Joint session of DS and O, organized by O)

DS 17.4: 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 Bellini^1,2, 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).