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Engineering electron pathways in 2D-topological insulators

A recently published research, lead by Reyes Calvo, Ikerbasque Fellow at CIC nanoGUNE, and Fernando de Juan, currently at Rudolf Peierls Centre for Theoretical Physics, Oxford and joining the Donostia International Phisics Centre (DIPC) as Ikerbasque Fellow in 2018, reports the interplay of quantum edge states across a lateral junction in a HgTe quantum well, a canonical 2D topological insulator. From their results, they extract new information on the fundamental properties of topological edge states and propose strategies to fine-tune their interaction.

"In our work, we test the consequences that allowing electrons to turn have in the conduction of our devices. We also show how under certain circumstances, electrons allowed to return seem to do it in an orderly manner, as if in some kind of round-about, generating a constructive interference.", Calvo explains.

This work contributes new insight into the fundamental properties of the edge states and their conduction properties in 2D-topological insulators. This kind of proposals to control the properties and interactions of these states are key for their application in the development of a new generation of electronic devices based on quantum fundamental properties of materials.

Reference:
Interplay of Chiral and Helical States in a Quantum Spin Hall Insulator Lateral Junction; M. R. Calvo, F. de Juan, R. Ilan, E. J. Fox, A. J. Bestwick, M. Mühlbauer, J. Wang, C. Ames, P. Leubner, C. Brüne, S. C. Zhang, H. Buhmann, L. W. Molenkamp, and D. Goldhaber-Gordon; Phys. Rev. Lett. 119, 226401 – Published 29 November 2017. DOI: https://doi.org/10.1103/PhysRevLett.119.226401