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28 May 2017 to 2 June 2017
Queen's University
America/Toronto timezone
Welcome to the 2017 CAP Congress! / Bienvenue au congrès de l'ACP 2017!

Gate-tunable valley currents, non-local resistances and valley accumulation in bilayer graphene nanostructures

30 May 2017, 15:30
15m
BioSci 1102 (Queen's University)

BioSci 1102

Queen's University

CLOSED - Oral (Student, In Competition) / Orale (Étudiant(e), inscrit à la compétition) Condensed Matter and Materials Physics / Physique de la matière condensée et matériaux (DCMMP-DPMCM) T4-1 Thin Films (DCMMP) | Couches minces (DPMCM)

Speaker

Mohammadhadi Azari (Simon Fraser University)

Description

Using the Büttiker-Landauer formulation of transport theory in the linear response regime, the valley currents and non-local resistances of bilayer graphene nanostructures with broken inversion symmetry are calculated. It is shown that broken inversion symmetry in bilayer graphene nanostructures leads to striking enhancement of the non-local 4-terminal resistance and to valley currents several times stronger than the conventional electric current when the Fermi energy is in the spectral gap close to the energy of Dirac point. The scaling relation between local and non-local resistances is investigated as the gate voltage varies at zero Fermi energy and a power-law is found to be satisfied. The valley velocity field and valley accumulation in four-terminal bilayer graphene nanostructures are evaluated in the presence of inversion symmetry breaking. The valley velocity and non-local resistance are found to scale differently with the applied gate voltage. The unit cell-averaged valley accumulation is found to exhibit a dipolar spatial distribution consistent with the accumulation arising from the valley currents. We define and calculate a valley capacitance that characterizes the valley accumulation response to voltages applied to the nanostructure's contacts.

Authors

Mohammadhadi Azari (Simon Fraser University) Prof. George Kirczenow (Physics Department of Simon Fraser University)

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