ELFT HÍRADÓ

[SIMON Ferenc <f.simon AT eik.bme.hu>]

MEGHÍVÓ

A BME Fizika Tanszék szemináriumára:

Dr. Martin Gmitra
University of Regensburg, Germany

Spin-orbit coupling in graphene, few-layer graphene structures, graphite 
and role of functionalization

Időpont: 2016. április 12. (kedd) 10.00
Hely: BME, F. epulet, I. lépcsőhaz, 1. emelet, Schay terem
megközelítes: https://www.google.hu/maps/ AT 47.479918,19.0547192,19z

Minden érdeklődőt szeretettel várunk!
Üdvözlettel
Simon Ferenc

Absztrakt:

The spin-orbit interaction as a relativistic interaction destroys the 
ideal relativistic "touching cones" of electronic dispersion at the Dirac 
point in graphene. It opens a gap of tenths of micro eV. It turns out that 
this essentially sp material has its spin-orbit coupling derived almost 
exclusively from d-orbitals [1]. Few-layer graphene structures may be 
potentially useful for optical and transport applications, due to the 
possibility of electrical control of the band gaps. We show, by performing 
first-principles full potential linearized augmented plane waves 
calculations, that the spin-orbit physics in these structures and in 
graphite derives essentially from monolayer graphene. In particular, the 
spin splitting of the bands is due to the spin-orbit coupling of the 
d-orbitals. These give a splitting of the order of 24 microeV at the K 
point, as in graphene. Breaking the spatial inversion symmetry by a transverse 
electric field does not change this (intrinsic) picture, unlike what we 
know from graphene. Functionalization of graphene by adatoms or 
admolecules gives rise to an enhancement of spin splitting due to new 
principal linear spin-orbit band splittings driven by the breaking of the 
local pseudospin inversion symmetry and the emergence of spin flips on the 
same sublattice [2].

[1] M. Gmitra et al., Phys. Rev. B 80, 235431 (2009); S. Konschuh et al., 
Phys. Rev. B 82, 245412 (2010); S. Konschuh et al., Phys. Rev. B 85, 
115423 (2012).
[2] M. Gmitra et al., Phys. Rev. Lett. 110, 246602 (2013); S. Irmer et 
al., Phys. Rev. B 91, 115141 (2015); K. Zollner et al., Phys. Rev. B 93, 
045423 (2016).


----------------------------
Prof. Ferenc SIMON
BME Fizikai Intézet, Igazgatóhelyettes
TU-Budapest, Institute of Physics, deputy director
http://physics.bme.hu/kapcsolat
http://goliat.eik.bme.hu/~f.simon/
ph. lab.:               (36-1) 463-1215
fax:                    (36-1) 463-4180
mob.:                   36-30-452-4705