相关论文: Ultrafast valley polarization in bilayer graphene

Bilayer graphene has drawn significant attention due to the opening of a band gap in its low energy electronic spectrum, which offers a promising route to electronic applications. The gap can be either tunable through an external electric…

We study the electron scattering produced by local out-of-plane strain deformations in the form of Gaussian bumps in graphene. Of special interest is to take into account the scalar field associated with the redistribution of charge due to…

Abstract The valley degree of freedom in two-dimensional materials provides an opportunity to extend the functionalities of valleytronics devices. Very short valley lifetimes demand the ultrafast control of valley pseudospin. Here, we…

The ability to resolve the polarization of light with on-chip devices represents an urgent problem in optoelectronics. The detectors with polarization resolution demonstrated so far mostly require multiple oriented detectors or movable…

Manipulating the circular polarization of light is of great importance in chemistry and biology, as chiral molecules exhibit different physiological properties when exposed to different circularly polarized waves. Here we suggest a…

We predict a strong-field ultrafast optical Faraday effect, where a circularly polarized ultrashort optical pulse induces transient chirality in an achiral transparent dielectric. This effect is attractive for time-resolved measurements…

We study theoretically the electron dynamics of transition metal dichalcogenide quantum dots in the field of an ultrashort and ultrafast circularly polarized optical pulse. The quantum dots have the shape of a disk and their electron…

We theoretically demonstrate the possibility to tune the temporal waveform of optical unipolar pulses upon their coherent interaction with a multi-level resonant medium. This is achieved through the coherent control of the response of a…

We theoretically study valley-filtering in pristine graphene irradiated by bicircular counter-rotating laser drive. The dynamical symmetry of the graphene and laser drive disrupts graphene's inversion symmetry, which results distinct…

Patterned graphene, as an atomically thin layer, supports localized surface plasmon-polaritons (LSPPs) at mid-infrared or far-infrared frequencies. This provides a pronounced optical force/torque in addition to large optical cross sections…

We calculate the ferroelectric polarization dynamics induced by a femtosecond midinfrared pulse as measured in the recent experiment by R. Mankowsky et al., Phys. Rev. Lett. 118, 197601 (2017). It is due to the nonlinear coupling of the…

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 electron transmission between monolayer and bilayer graphene is theoretically studied for zigzag and armchair boundaries within an effective-mass scheme. Due to the presence of an evanescent wave in the bilayer graphene, traveling modes…

We address the intrinsic polarisation and screening of external electric field in a broad range of ordered and twisted configurations of multilayer graphene, using an ab initio approach combining density functional theory and the Wannier…

The valley degree of freedom in 2D materials can be manipulated for low-dissipation quantum electronics called valleytronics. At the boundary between two regions of bilayer graphene with different atomic or electrostatic configuration,…

Sculpting sub-cycle temporal structures of optical waveforms allows one to image and even control electronic clouds in atoms, molecules and solids. Here we show how the transverse spin component arising upon spatial confinement of such…

Highly polarized components of pulse profiles are investigated by analyzing observational data and simulating the emission processes. The highly polarized components appear at the leading or trailing part of a pulse profile, which…

The shape of a few-cycle terahertz (THz) laser pulse can be optimized to provide control over conduction band populations in graphene. To demonstrate this control in a theoretical way, a spectral parametrization of the driving pulse using…

In addition to electron charge and spin, novel materials host another degree of freedom, the valley. For a junction composed of valley filter sandwiched by two normal terminals, we focus on the valley efficiency under disorder with two…

Because the valleys in the band structure of graphene are related by time-reversal symmetry, electrons from one valley are reflected as holes from the other valley at the junction with a superconductor. We show how this Andreev reflection…