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Seminar - Sanjoy K. Mahatha

Title: Absence of Dirac cones in monolayer silicene and multilayer Si films on Ag(111)

Info about event

Time

Wednesday 18 May 2016,  at 11:00 - 12:30

 

Talk by Sanjoy K. Mahatha

Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, I-34149 Trieste, Italy

 

Titel: Absence of Dirac cones in monolayer silicene and multilayer Si films on Ag(111)

Abstract: Honeycomb structured (4×4) monolayer silicene and (?3×?3)R30° multilayer silicon on Ag(111) have attracted a lot of interest with photoemission studies indicating the presence of ?-band Dirac cones near the Fermi level.1,2 In this talk, I will show instead that the ?-symmetry states of monolayer silicene lose their local character and the Dirac cones fade out. An interface state of free-electron-like Ag origin accounts for the spectral features that were attributed to silicene ?-bands.3,4 For multilayer silicon, the bands previously attributed to ?* state with Dirac fermion character are found to derive from the well-known Ag- (?3×?3)R30°-Si(111) structure, and from a Si modified Ag(111) interface states.5 

 

 

1 P. Vogt et al., Phys. Rev. Lett. 108, 155501 (2012).

2 P. De Padova et al., Appl. Phys. Lett. 102, 163106 (2013), J. Phys.: Condens. Matter 25 382202 (2013).

3 D. Tsoutsou et al., Appl. Phys. Lett. 103, 231604 (2013).

4 S. K. Mahatha et al., Phys. Rev. B 89, 201416(R) (2014).

5 S. K. Mahatha et al., Phys. Rev. B 92, 245127 (2015).