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Condensed Matter Physics

University of Kentucky

Series

2-dimensional systems

Publication Year

Articles 1 - 2 of 2

Full-Text Articles in Physics

Relaxation Of Charge In Monolayer Graphene: Fast Nonlinear Diffusion Versus Coulomb Effects, Eugene B. Kolomeisky, Joseph P. Straley Jan 2017

Relaxation Of Charge In Monolayer Graphene: Fast Nonlinear Diffusion Versus Coulomb Effects, Eugene B. Kolomeisky, Joseph P. Straley

Physics and Astronomy Faculty Publications

Pristine monolayer graphene exhibits very poor screening because the density of states vanishes at the Dirac point. As a result, charge relaxation is controlled by the effects of zero-point motion (rather than by the Coulomb interaction) over a wide range of parameters. Combined with the fact that graphene possesses finite intrinsic conductivity, this leads to a regime of relaxation described by a nonlinear diffusion equation with a diffusion coefficient that diverges at zero charge density. Some consequences of this fast diffusion are self-similar superdiffusive regimes of relaxation, the development of a charge depleted region at the interface between electron- and …


Emergence Of Helical Edge Conduction In Graphene At The Ν = 0 Quantum Hall State, Pavel Tikhonov, Efrat Shimshoni, H. A. Fertig, Ganpathy Murthy Mar 2016

Emergence Of Helical Edge Conduction In Graphene At The Ν = 0 Quantum Hall State, Pavel Tikhonov, Efrat Shimshoni, H. A. Fertig, Ganpathy Murthy

Physics and Astronomy Faculty Publications

The conductance of graphene subject to a strong, tilted magnetic field exhibits a dramatic change from insulating to conducting behavior with tilt angle, regarded as evidence for the transition from a canted antiferromagnetic (CAF) to a ferromagnetic (FM) ν = 0 quantum Hall state. We develop a theory for the electric transport in this system based on the spin-charge connection, whereby the evolution in the nature of collective spin excitations is reflected in the charge-carrying modes. To this end, we derive an effective field-theoretical description of the low-energy excitations, associated with quantum fluctuations of the spin-valley domain-wall ground-state configuration which …