Topological Insulators - GDR Meso

Anisotropic Scattering of Dirac states
Consider Dirac surface states with
‣ phase coherence (small sample, low T)
Hexagonal warping :
‣ scalar disorder
‣ semi-classical limit
H W = 2
z k 3 + + k 3 k ± = k x ± ik y
H 0 = ~v F ẑ ⇥ (~ ⇥ ~ k)
+V (~r )
(high doping in the gap)
L. Fu, PRL 103 (2009)
‣ allowed by Time Reversal Symmetry (same univ. class)
‣ experimentally extracted value in TI : bw=0.4-0.6
‣ important at high kF (weak localization regime)
‣ Perturbative parameter (deformation of Fermi surface) bw
➡ depends on EF
k min
kmax
b w =
E2 F
2~ 3 v 3 F
w = w max
1
k min
k max
1+ k min
k max
Z. Alpichshev et al., PRL 104 (2010)
S.Y. Xu et al., (2011)
mardi 3 janvier 12