相关论文: Light-induced valley currents and magnetization in…
We study theoretically the charge polarization and the charge current dynamics of a mesoscopic ring driven by short asymmetric electromagnetic pulses and threaded by an external static magnetic flux. It is shown that the pulse-induced…
The theoretical results are presented showing that strain-induced anisotropy of graphene spectrum gives rise to the valley currents under the illumination by normally incident light. The currents of the two graphene valleys are mutually…
Recent experiments have revealed that novel nonequilibrium states consistent with the hydrodynamic description of electrons are realized in ultrapure graphene, which hosts the valley degrees of freedom. Here, we formulate a theory of…
We show that the optical excitation of graphene with polarized light leads to the pure valley current where carriers in the valleys counterflow. The current in each valley originates from asymmetry of optical transitions and electron…
Persistent currents can arise in normal-metal rings due to a magnetic flux threading the ring in equilibrium. However, can persistent currents arise in absence of magnetic flux in the same normal-metal rings? Yes they can but in a…
The ability to manipulate electrons with the intense laser pulse enables an unprecedented control over the electronic motion on its intrinsic timescale. Present work explores the desired control of photocurrent generation in monolayer…
Magic-angle twisted bilayer graphene displays a complex phase diagram as a function of flat band filling, featuring compressibility cascade transitions and a variety of competing ground states with broken spin, valley and point group…
We study the conductance of mesoscopic graphene rings in the presence of a perpendicular magnetic field by means of numerical calculations based on a tight-binding model. First, we consider the magnetoconductance of such rings and observe…
Valley polarization in graphene breaks inversion symmetry and therefore leads to second-harmonic generation. We present a complete theory of this effect within a single-particle approximation. It is shown that this may be a sensitive tool…
We investigate a valleytronic device based on graphene with charge separation at different sublattices and correspondingly at nonequivalent valleys. We characterize the maximality condition of valley polarization and investigate the…
For gapped graphene, we predict that an intense ultrashort (single-oscillation) circularly-polarized optical pulse can induce a large population of the conduction band and a large valley polarization. With an increase in the bandgap, the…
We study theoretically the interaction of ultrashort optical pulses with gapped graphene. Such strong pulse results in finite conduction band population and corresponding electric current both during and after the pulse. Since gapped…
Graphene, and other members of the monolayer Xene family, represent an ideal materials platform for "valleytronics", the control of valley localized charge excitations. The absence of a gap in these semi-metals, however, precludes valley…
Achieving a population imbalance between the two inequivalent valleys is a critical first step for any valleytronic device. A valley-polarization can be induced in biased bilayer graphene using circularly polarized light. In this paper, we…
Electrons in two-dimensional hexagonal materials have valley degree of freedom, which can be used to encode and process quantum information. The valley-selective excitations, governed by the circularly polarised light resonant with the…
The valley degeneracy of electron states in graphene stimulates intensive research of valley-related optical and transport phenomena. While many proposals on how to manipulate valley states have been put forward, experimental access to the…
Well established for the visible spectrum gaps of the transition metal dichalcogenide family, valleytronics - the control of valley charge and current by light - is comparatively unexplored for the THz gaps that characterize graphene and…
We study theoretically interaction of a bilayer graphene with a circularly polarized ultrafast optical pulse of a single oscillation at an oblique incidence. The normal component of the pulse breaks the inversion symmetry of the system and…
We recently shown, using tight-binding calculations, that nonequilibrium valley polarization can be realized in graphene, when the current is injected through "valley filter": a ballistic point contact with zigzag edges. Here we…
We report on the possibility to simultaneously generate in graphene a {\it bulk valley-polarized dissipative transport} and a {\it quantum valley Hall effect} by combining strain-induced gauge fields and real magnetic fields. Such unique…