2012/02/29 by R. Buczko, Ryszard Buczko, Łukasz Cywiński
Materials Science · Physics and Astronomy · #2D Materials and Applications #Condensed matter physics #Dirac fermion #Fermion #Gapless playback #Geometry #Graphene research and applications #Heterojunction #Materials science #Physics #Quantum mechanics #Quantum well #Semiconductor #Surface (topology) #Surface states #Topological Materials and Phenomena #Topological insulator #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.85.205319
published as Phys. Rev. B 85, 205319 (2012) · 6 pages, 4 figures, final version published in Phys. Rev. B
openalex publication_date 2012/05/29 · arxiv created 2012/05/30 · arxiv updated 2012/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate theoretically the PbTe/Pb_1\ensuremath-xSnxTe heterostructure grown in the [111] direction, specifically a quantum wall (potential step of width d) of PbTe embedded in Pb_1\ensuremath-xSnxTe. 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\ensuremath≈10 nm, the three pairs of states from oblique valleys strongly couple and become gapped with a gap \ensuremath∼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. This opens up a possibility of studying the physics of two-dimensional helical Dirac fermions in heterostuctures of already widely studied IV-VI semiconductors.