Wednesday, October 17, 2012

1210.4422 (Tomi Paananen et al.)

Magnetically robust topological edge states and flat bands    [PDF]

Tomi Paananen, Thomas Dahm
We study thin strips of three dimensional topological insulators in the presence of a spin-splitting Zeeman field. We show that under certain conditions the topological edge states at the sides of a strip remain robust against a time-reversal symmetry breaking Zeeman field. For a particle-hole symmetric system with Zeeman field perpendicular to the strip we strictly proof that the dispersion and the spin-orbital structure of the edge states remains unchanged. When the Zeeman field lies parallel to the strip, the Dirac spectrum becomes flat, but remains intact. Above a critical value of the Zeeman field a completely flat surface band develops. We present numerical calculations for a realistic tight-binding model of Bi$_2$Se$_3$. These calculations show that even though particle-hole symmetry is not strictly fulfilled in this system, these special features are still present.
View original:

No comments:

Post a Comment