Abstract
The Corbino geometry allows one to investigate the propagation of electric current along a p–n interface in ballistic graphene in the absence of edge states appearing for the familiar Hall-bar geometry. Using the transfer matrix in the angular-momentum space we find that for sufficiently strong magnetic fields the current propagates only in one direction, determined by the magnetic field direction and the interface orientation, and the two valleys, K and K′, are equally occupied. Spatially-anisotropic effective mass may suppress one of the valley currents, selected by the external electric field, transforming the system into a mesoscopic version of the valley filter. The filtering mechanism can be fully understood within the effective Dirac theory, without referring to atomic-scale effects which are significant in proposals operating on localized edge states.
Highlights
One-dimensional conduction channels associated with edge states are often considered as background for solidstate quantum information processing in systems showing the quantum Hall effect [1,2,3,4,5,6,7,8], and in graphene [9, 10] or transition metal dichalcogenide nanoribbons [11]
We explore the possibility of valley filtering for peculiar edge states mixing Landau levels from both sides of the p–n interface in the quantum Hall regime [4,5,6]
As a proof of principle, that the Corbino disk in monolayer graphene modified such that the mass term in effective Dirac equation is present in a half of the disk may act as a highly efficient valley filter, when placed in crossed electric and magnetic fields inducing a p–n interface close to the mass-region boundary
Summary
The Corbino geometry allows one to investigate the propagation of electric current along a p–n licence. Interface in ballistic graphene in the absence of edge states appearing for the familiar Hall-bar. Using the transfer matrix in the angular-momentum space we find that for sufficiently this work must maintain attribution to the strong magnetic fields the current propagates only in one direction, determined by the magnetic field author(s) and the title of the work, journal citation direction and the interface orientation, and the two valleys, K and K′, are occupied. Anisotropic effective mass may suppress one of the valley currents, selected by the external electric field, transforming the system into a mesoscopic version of the valley filter. The filtering mechanism can be fully understood within the effective Dirac theory, without referring to atomic-scale effects which are significant in proposals operating on localized edge states
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