Related papers: High-purity valley-polarized currents induced by b…
Valleytronics is rapidly emerging as an exciting area of basic and applied research. In two dimensional systems, valley polarisation can dramatically modify physical properties through electron-electron interactions as demonstrated by such…
The valley degree of freedom in layered transition-metal dichalcogenides (MX2) provides the opportunity to extend functionalities of novel spintronics and valleytronics devices. Due to spin splitting induced by spin-orbital coupling (SOC),…
Some semiconductors have more than one degenerate minimum of the conduction band in their band structure. These minima-known as valleys-can be used for storing and processing information, if it is possible to generate a difference in their…
Here we proposed the valley selective excitations via a two-color (\ensuremath{\omega} + \ensuremath{2\omega}) laser field, made by superimposing two linearly polarized pulses at frequencies \ensuremath{\omega} and \ensuremath{2\omega}. We…
The electron transport of different conical valleys is investigated in graphene with extended line-defects. Intriguingly, the electron with a definite incident angle can be completely modulated into one conical valley by a resonator which…
Analogous to charge and spin, electrons in solids endows an additional degree of freedom: the valley pseudospin. Two-dimensional hexagonal materials such as graphene exhibit two valleys, labelled as $\mathbf{K}$ and $\mathbf{K}^{\prime}$.…
Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional opto-electronics. In their monolayer form they host electrons with quantized circular…
Valley, as a new degree of freedom for electrons, has drawn considerable attention due to its significant potential for encoding and storing information. Lifting the energy degeneracy to achieve valley polarization is necessary for…
Recent advances in condensed matter physics have shown that the valley degree of freedom of electrons in 2D materials with hexagonal symmetry, such as graphene, h-BN, and TMDs, can be efficiently exploited, leading to the emergent field of…
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…
Spatial heterogeneity and phase competition are hallmarks of strongly-correlated materials, promising tunable functionality on the nanoscale. Light-induced switching of a correlated insulator to a metallic state is well established.…
Using a high-frequency field superposed to a linearly polarized bichromatic laser field composed by a wave with frequency $\omega $ and a wave with frequency $2\omega $, we show it is possible to enhance the intensity of a group of high…
Active control of optical nonlinearity is essential for advancing next-generation electronics and photonics, including high-speed wireless communications, optical information processing, and nonlinear signal manipulation. However, achieving…
Coherent radiation with frequencies ranging from 0.3 to 30 THz has recently become accessible by femtosecond laser technology. Terahertz (THz) waves have already found many applications in spectroscopy and imaging, and they can be…
We studied the high-order harmonic generation (HHG) from 2D solid materials in circularly and bichromatic circularly polarized laser fields numerically by simulating the dynamics of single-active-electron processes in 2D periodic…
We predict high-order harmonics in which the polarization within the spectral bandwidth of each harmonic varies continuously and significantly. For example, the interaction of counter-rotating circularly-polarized bichromatic drivers having…
Sixfold-degenerate valleys in Si have attracted considerable attention for valleytronics application. Using optical pump-terahertz (THz) probe spectroscopy, we study the dynamics of valley polarization in bulk Si(001) at room temperature.…
We reveal an instantaneous optical valley selection rule that illuminates the coupling between the instantaneous optical chirality of the driving laser field and the chirality of valley systems. Building on this principle, we propose and…
Nonlinear interactions between ultrashort optical waveforms and solids can be used to induce and steer electric current on a femtosecond (fs) timescale, holding promise for electronic signal processing at PHz frequencies [Nature 493, 70…
A valley filter capable of generating a valley-polarized current is a crucial element in valleytronics, yet its implementation remains challenging. Here, we propose a valley filter made of a graphene bilayer which exhibits a 1D moir\'{e}…