Tuning the valley and chiral quantum state of Dirac electrons in van der Waals heterostructures
Authors: J. R. Wallbank, D. Ghazaryan, A. Misra, Y. Cao, J. S. Tu, B. A. Piot, M. Potemski, S. Pezzini, S. Wiedmann, U. Zeitler, T. L. M. Lane, S. V. Morozov, M. T. Greenaway, L. Eaves, A. K. Geim, V. I. Fal'ko, K. S. Novoselov, A. Mishchenko
Publication Date: 05 August, 2016
Department of: Physics and Astronomy
Teasing out chirality in graphene
Researchers at the University of Manchester and the National Graphene Institute have reported the direct observation and manipulation of chirality and pseudospin in electrons that tunnel between two layers of graphene. Pseudospin is a property of electrons in graphene that arises due to the crystal structure of the material. Chirality is the projection of the pseudospin onto the electron’s direction of motion and is analogous to the chiral properties of elementary particles.
The researchers studied how electrons tunnel between two slightly misaligned graphene sheets (separated by a layer of insulating material) after applying a strong in-plane magnetic field to resolve the contributions of the chiral states. The chiral nature of the electrons imposed restrictions on the tunnelling, which made it possible to discern the signals of chirality in the data. A key outcome of this research is the demonstration that electrons with well-controlled pseudospin can be injected into graphene. The possibility to control these degrees of freedom in the future opens the door to ever more precise manipulation in new forms of semiconductor electronics such as ‘chirotronics’ and ‘valleytronics’.
- National Graphene Institute
- Centre for Mesoscience and Nanotechnology
- LNCMI-CNRS-UGA-UPS-INSA-EMFL, Grenoble
- HFML-EMFL, Nijmegen
- Institute of Microelectronics Technology and High Purity Materials, Chernogolovka National Institute of Science and Technology, Moscow
- School of Physics and Astronomy, University of Nottingham