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Philip Hofmann

Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator Heterostructures

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  • Craig M. Polley, Lund University
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  • Ryszard Buczko, Polish Acad Sci, Polish Academy of Sciences, Institute of Nuclear Physics - Polish Academy of Sciences, Henryk Niewodniczanski Inst Nucl Phys
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  • Alexander Forsman, KTH Royal Inst Technol, Royal Institute of Technology, SCI Mat Phys
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  • Piotr Dziawa, Polish Acad Sci, Polish Academy of Sciences, Institute of Nuclear Physics - Polish Academy of Sciences, Henryk Niewodniczanski Inst Nucl Phys
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  • Andrzej Szczerbakow, Polish Acad Sci, Polish Academy of Sciences, Institute of Nuclear Physics - Polish Academy of Sciences, Henryk Niewodniczanski Inst Nucl Phys
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  • Rafal Rechcinski, Polish Acad Sci, Polish Academy of Sciences, Institute of Nuclear Physics - Polish Academy of Sciences, Henryk Niewodniczanski Inst Nucl Phys
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  • Bogdan J. Kowalski, Polish Acad Sci, Polish Academy of Sciences, Institute of Nuclear Physics - Polish Academy of Sciences, Henryk Niewodniczanski Inst Nucl Phys
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  • Tomasz Story, Polish Acad Sci, Polish Academy of Sciences, Institute of Nuclear Physics - Polish Academy of Sciences, Henryk Niewodniczanski Inst Nucl Phys
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  • Malgorzata Trzyna, Rzeszow Univ, University of Rzeszow, Ctr Microelect & Nanotechnol
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  • Marco Bianchi
  • Antonija Grubisic Cabo
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  • Philip Hofmann
  • Oscar Tjernberg, KTH Royal Inst Technol, Royal Institute of Technology, SCI Mat Phys
  • ,
  • Thiagarajan Balasubramanian, Lund University

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 (X) over bar 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.

OriginalsprogEngelsk
TidsskriftA C S Nano
Vol/bind12
Nummer1
Sider (fra-til)617-626
Antal sider10
ISSN1936-0851
DOI
StatusUdgivet - jan. 2018

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