Bulk and interface quantum states of electrons in multi-layer heterostructures with topological materials.
Journal of Physics Condensed Matter
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Nikolic, A., Zhang, K., & Barnes, C. (2018). Bulk and interface quantum states of electrons in multi-layer heterostructures with topological materials.. Journal of Physics Condensed Matter, 30 (23. 235001)https://doi.org/10.1088/1361-648X/aac0b1
In this article we describe the bulk and interface quantum states of electrons in multi-layer heterostructures in one dimension, consisting of topological insulators (TIs) and topologically trivial materials. We use and extend an effective four-band continuum Hamiltonian by introducing position dependence to the eight material parameters of the Hamiltonian. We are able to demonstrate complete conduction-valence band mixing in the interface states. We find evidence for topological features of bulk states of multi-layer TI heterostructures, as well as demonstrating both complete and incomplete conduction-valence band inversion at different bulk state energies. We show that the linear k z terms in the low-energy Hamiltonian, arising from overlap of p z orbitals between different atomic layers in the case of chalcogenides, control the amount of tunneling from TIs to trivial insulators. Finally, we show that the same linear k z terms in the low-energy Hamiltonian affect the material's ability to form the localised interface state, and we demonstrate that due to this effect the spin and probability density localisation in a thin film of Sb2Te3 is incomplete. We show that changing the parameter that controls the magnitude of the overlap of p z orbitals affects the transport characteristics of the topologically conducting states, with incomplete topological state localisation resulting in increased backscattering.
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External DOI: https://doi.org/10.1088/1361-648X/aac0b1
This record's URL: https://www.repository.cam.ac.uk/handle/1810/280601
Attribution 4.0 International
Licence URL: http://creativecommons.org/licenses/by/4.0/
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