1202.2315 (Ryszard Buczko et al.)

PbTe/PbSnTe heterostructures as analogues of topological insulators    [PDF]

Ryszard Buczko, Łukasz Cywiński

We investigate theoretically the PbSnTe/PbTe heterostructure grown in [111]
direction, specifically a quantum wall (potential step of width d) of PbTe
embedded in Pb_{1-x}Sn_{x}Te. For x large enough to lead to band inversion, and
for large d, there are well-known gapless interface states associated with four
L valleys. We show that for d \approx 10 nm the three pairs of states from
oblique valleys strongly couple, and become gapped with a gap ~10 meV. On the
other hand, the interface states from the [111] valley are essentially
uncoupled, and they retain their helical character, remaining analogous to
states at surfaces of thin layers of three-dimensional topological insulators.

View original: http://arxiv.org/abs/1202.2315