Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator Heterostructures
(2018) In ACS Nano 12(1). p.617-626- Abstract
The "double Dirac cone" 2D topological interface states found on the (001) faces of topological crystalline insulators such as Pb1-xSnxSe feature degeneracies located away from time reversal invariant momenta and are a manifestation of both mirror symmetry protection and valley interactions. Similar shifted degeneracies in 1D interface states have been highlighted as a potential basis for a topological transistor, but realizing such a device will require a detailed understanding of the intervalley physics involved. In addition, the operation of this or similar devices outside of ultrahigh vacuum will require encapsulation, and the consequences of this for the topological interface state must be understood. Here we... (More)
The "double Dirac cone" 2D topological interface states found on the (001) faces of topological crystalline insulators such as Pb1-xSnxSe feature degeneracies located away from time reversal invariant momenta and are a manifestation of both mirror symmetry protection and valley interactions. Similar shifted degeneracies in 1D interface states have been highlighted as a potential basis for a topological transistor, but realizing such a device will require a detailed understanding of the intervalley physics involved. In addition, the operation of this or similar devices outside of ultrahigh vacuum will require encapsulation, and the consequences of this for the topological interface state must be understood. Here we address both topics for the case of 2D surface states using angle-resolved photoemission spectroscopy. We examine bulk Pb1-xSnxSe(001) crystals overgrown with PbSe, realizing trivial/topological heterostructures. We demonstrate that the valley interaction that splits the two Dirac cones at each X̄ is extremely sensitive to atomic-scale details of the surface, exhibiting non-monotonic changes as PbSe deposition proceeds. This includes an apparent total collapse of the splitting for sub-monolayer coverage, eliminating the Lifshitz transition. For a large overlayer thickness we observe quantized PbSe states, possibly reflecting a symmetry confinement mechanism at the buried topological interface.
(Less)
- author
- organization
- publishing date
- 2018-01-23
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- angle-resolved photoemission spectroscopy (ARPES), quantum confinement, topological crystalline insulator, topological heterostructure, valley splitting
- in
- ACS Nano
- volume
- 12
- issue
- 1
- pages
- 10 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:85042198890
- pmid:29251489
- ISSN
- 1936-0851
- DOI
- 10.1021/acsnano.7b07502
- language
- English
- LU publication?
- yes
- id
- ea105ce3-dd1d-434a-a262-83ebdf692118
- date added to LUP
- 2018-03-07 09:52:10
- date last changed
- 2024-09-02 16:56:30
@article{ea105ce3-dd1d-434a-a262-83ebdf692118, abstract = {{<p>The "double Dirac cone" 2D topological interface states found on the (001) faces of topological crystalline insulators such as Pb<sub>1-x</sub>Sn<sub>x</sub>Se feature degeneracies located away from time reversal invariant momenta and are a manifestation of both mirror symmetry protection and valley interactions. Similar shifted degeneracies in 1D interface states have been highlighted as a potential basis for a topological transistor, but realizing such a device will require a detailed understanding of the intervalley physics involved. In addition, the operation of this or similar devices outside of ultrahigh vacuum will require encapsulation, and the consequences of this for the topological interface state must be understood. Here we address both topics for the case of 2D surface states using angle-resolved photoemission spectroscopy. We examine bulk Pb<sub>1-x</sub>Sn<sub>x</sub>Se(001) crystals overgrown with PbSe, realizing trivial/topological heterostructures. We demonstrate that the valley interaction that splits the two Dirac cones at each X̄ is extremely sensitive to atomic-scale details of the surface, exhibiting non-monotonic changes as PbSe deposition proceeds. This includes an apparent total collapse of the splitting for sub-monolayer coverage, eliminating the Lifshitz transition. For a large overlayer thickness we observe quantized PbSe states, possibly reflecting a symmetry confinement mechanism at the buried topological interface.</p>}}, author = {{Polley, Craig M. and Buczko, Ryszard and Forsman, Alexander and Dziawa, Piotr and Szczerbakow, Andrzej and Rechciński, Rafał and Kowalski, Bogdan J. and Story, Tomasz and Trzyna, Małgorzata and Bianchi, Marco and Grubišić Čabo, Antonija and Hofmann, Philip and Tjernberg, Oscar and Balasubramanian, Thiagarajan}}, issn = {{1936-0851}}, keywords = {{angle-resolved photoemission spectroscopy (ARPES); quantum confinement; topological crystalline insulator; topological heterostructure; valley splitting}}, language = {{eng}}, month = {{01}}, number = {{1}}, pages = {{617--626}}, publisher = {{The American Chemical Society (ACS)}}, series = {{ACS Nano}}, title = {{Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator Heterostructures}}, url = {{http://dx.doi.org/10.1021/acsnano.7b07502}}, doi = {{10.1021/acsnano.7b07502}}, volume = {{12}}, year = {{2018}}, }