Tuning the valley and chiral quantum state of Dirac electrons in van der Waals heterostructures

Wallbank, J.R. and Ghazaryan, D. and Misra, A. and Cao, Y. and Tu, J.S. and Piot, B.A. and Potemski, M. and Pezzini, S. and Wiedmann, S. and Zeitler, U. and Lane, T.L.M. and Morozov, S.V. and Greenaway, M.T. and Eaves, Laurence and Geim, A.K. and Fal'ko, V.I. and Novoselov, K.S. and Mishchenko, A. (2016) Tuning the valley and chiral quantum state of Dirac electrons in van der Waals heterostructures. Science, 353 (6299). pp. 575-579. ISSN 1095-9203

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Chirality is a fundamental property of electrons with the relativistic spectrum found in graphene and topological insulators. It plays a crucial role in relativistic phenomena, such as Klein tunneling, but it is difficult to visualize directly. Here we report the direct observation and manipulation of chirality and pseudospin polarization in the tunneling of electrons between two almost perfectly aligned graphene crystals. We use a strong in-plane magnetic field as a tool to resolve the contributions of the chiral electronic states that have a phase difference between the two components of their vector wavefunction. Our experiments not only shed light on chirality, but also demonstrate a technique for preparing graphene’s Dirac electrons in a particular quantum chiral state in a selected valley.

Item Type: Article
Additional Information: Supplementary information (3 pages) appears at http://science.sciencemag.org/content/suppl/2016/08/03/353.6299.575.DC1
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1126/science.aaf4621
Depositing User: Eaves, Laurence
Date Deposited: 03 Jan 2017 09:58
Last Modified: 03 Jan 2017 20:48
URI: http://eprints.nottingham.ac.uk/id/eprint/39486

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