Yury P. Bliokh

Electronic properties of mesoscopic graphene structures: Charge confinement and control of spin and charge transport

This brief review discusses electronic properties of mesoscopic graphene-based structures. These allow controlling the confinement and transport of charge and spin; thus, they are of interest not only for fundamental research, but also for applications. The graphene-related topics covered here are: edges, nanoribbons, quantum dots, pn-junctions, pnp-structures, and quantum barriers and waveguides. This review is partly intended as a short introduction to graphene mesoscopics.

Colloquium: Unusual resonators: Plasmonics, metamaterials, and random media

Superresolution, extraordinary transmission, total absorption, and localization of electromagnetic waves are currently attracting growing attention. These phenomena are related to different physical objects and are usually studied within the context of different, sometimes rather sophisticated, physical approaches. Remarkably, all these seemingly unrelated phenomena owe their origin to the same underlying physical mechanism - wave interaction with an open resonator. Here we show that it is possible to describe all of these effects in a unified way, mapping each system onto a simple resonator model. Such description provides a thorough understanding of the phenomena, explains all the main features of their complex behaviour, and enables to control the system via the resonator parameters: eigenfrequencies, Q-factors, and coupling coefficients.

Semiclassical dynamics of electron wave packet states with phase vortices.

We consider semiclassical higher-order wave packet solutions of the Schrödinger equation with phase vortices. The vortex line is aligned with the propagation direction, and the wave packet carries a well-defined orbital angular momentum (OAM) variant Plancks over 2pil (l is the vortex strength) along its main linear momentum. The probability current coils around the momentum in such OAM states of electrons. In an electric field, these states evolve like massless particles with spin l. The magnetic-monopole Berry curvature appears in momentum space, which results in a spin-orbit-type interaction and a Berry/Magnus transverse force acting on the wave packet. This brings about the OAM Hall effect. In a magnetic field, there is a Zeeman interaction, which, can lead to more complicated dynamics.

TOTAL ABSORPTION OF AN ELECTROMAGNETIC WAVE BY AN OVERDENSE PLASMA

We show both theoretically and experimentally that an electromagnetic wave can be totally absorbed by an overdense plasma when a subwavelength diffraction grating is placed in front of the plasma surface. The absorption is due to dissipation of surface plasma waves (plasmons polaritons) that have been resonantly excited by the evanescent component of the diffracted electromagnetic wave. The developed theoretical model allows one to determine the conditions for the total absorption.

Transport and localization in periodic and disordered graphene superlattices

We study the transport of low-energy charged quasiparticles in graphene superlattices created by applying either periodic or disordered smooth scalar potentials, which cause no intervalley scattering. It is shown that the transport and spectral properties of such structures are strongly anisotropic. In the direction perpendicular to the layers, the eigenstates in a disordered sample are delocalized for all energies and provide a minimum nonzero conductivity, which cannot be destroyed by disorder, no matter how strong this is. However, along with extended states, there exist discrete sets of angles and energies with exponentially localized eigenfunctions (disorder-induced resonances). Owing to these features, such samples could be used as building blocks in tunable electronic circuits. It is shown that, depending on the type of the unperturbed system, the disorder could either suppress or enhance the transmission. Remarkable properties of the transmission have been found in graphene systems built of alternating

Resonant plasmon-soliton interaction

p\text{\ensuremath{-}}n

Tunable electronic transport and unidirectional quantum wires in graphene subjected to electric and magnetic fields

and

Coupling and level repulsion in the localized regime: from isolated to quasiextended modes.

n\text{\ensuremath{-}}p

Ballistic charge transport in graphene and light propagation in periodic dielectric structures with metamaterials: A comparative study

junctions. The mean transmission coefficient has anomalously narrow angular spectrum, practically independent of the amplitude of the fluctuations of the potential. To better understand the physical implications of the results presented here, most of these have been compared with the results for analogous electromagnetic wave systems. Along with similarities, a number of quite surprising differences have been found.

Broad-band polarization-independent absorption of electromagnetic waves by an overdense plasma

We describe an effective resonant interaction between two localized wave modes of different nature: a plasmon polariton at a metal surface and a self-focusing beam (spatial soliton) in a nonlinear dielectric medium. Propagating in the same direction, they represent an exotic coupled-waveguide system, where the resonant interaction is controlled by the soliton amplitude. This nonlinear system manifests hybridized plasmon-soliton eigenmodes, mutual conversion, and nonadiabatic switching, which offer exciting opportunities for manipulation of plasmons via spatial solitons.