相关论文: Optical absorption window in Na$_3$Bi based three-…
We present results for the optical conductivity of Na2IrO3 within density functional theory by including spin-orbit (SO) and correlation effects (U) as implemented in GGA+SO+U. We identify the various interband transitions and show that the…
Within the tight binding approximation, we study the dependence of the electronic band structure and of the optical conductivity of a graphene single layer on the modulus and direction of applied uniaxial strain. While the Dirac cone…
The inter-band optical absorption in graphene characterized by its fine-structure constant has a universal value of 2.3\% independent of the material parameters. However, for several graphene-based photonic applications, enhanced optical…
We report on simulations and measurements of the optical absorption of silicon nanowires (NWs) versus their diameter. We first address the simulation of the optical absorption based on two different theoretical methods : the first one,…
We compute the optical conductivity of graphene beyond the usual Dirac cone approximation, giving results that are valid in the visible region of the conductivity spectrum. The effect of next nearest neighbor hoping is also discussed. Using…
Graphene is a 2-dimensional material with high carrier mobility and thermal conductivity, suitable for high-speed electronics. Conduction and valence bands touch at the Dirac point. The absorptivity of single-layer graphene is 2.3%, nearly…
The infrared range optical absorption mechanism of Carbon-Copper composite thin layer coated on the Diamond-Like Carbon (DLC) buffer layer has been investigated. By consideration of weak interactions between copper nanoparticles in their…
We address the optical conductivity of undoped bilayer graphene in the presence of a finite bias voltage at finite temperature. The effects of gap parameter and stacking type on optical conductivity are discussed in the context of tight…
We present temperature-dependent infrared spectroscopic studies of CaMnSb2, a proposed threedimensional topological material. The low plasma edge in the reflectivity spectrum and small Drude component in the optical conductivity indicate a…
We study transport across a time-dependent magnetic barrier present on the surface of a three-dimensional topological insulator. We show that such a barrier can be implemented for Dirac electrons on the surface of a three-dimensional…
Enhancing the light-matter interaction in two-dimensional (2D) materials with high-$Q$ resonances in photonic structures has boosted the development of optical and photonic devices. Herein, we intend to build a bridge between the radiation…
We have calculated the dynamical optical conductivity for $\alpha-\mathcal{T}_3$ materials in the presence of a finite bandgap in their energy bandstructure. This is a special type of energy dispersions because for all…
We present a theoretical study of the optical absorption spectrum of small boron-nitride and carbon nanotubes using time-dependent density-functional theory and the random phase approximation. Both for C and BN tubes, the absorption of…
Prototypical three-dimensional (3D) topological Dirac semimetals (DSMs), such as Cd$_3$As$_2$ and Na$_3$Bi, contain electrons that obey a linear momentum-energy dispersion with different Fermi velocities along the three orthogonal momentum…
We study optical properties of two dimensional silicene using density functional theory based calculations. Our results on optical response property calculations show that they strongly depend on direction of polarization of light, hence…
The efforts to pursue photo detection with extreme performance in terms of ultrafast response time, broad detection wavelength range, and high sensitivity have never been exhausted as driven by its wide range of optoelectronic and photonic…
Using Linear Response Theory, with appropriate wave functions and energies from perturbation method, the absorption profiles can be calculated for all three classes of mixed-valence systems as defined by Robin and Day : Class III…
Within a Kubo formalism, we calculate the absorptive part of the dynamic longitudinal conductivity $\sigma(\Omega)$ of a 2D semi-Dirac material. In the clean limit, we provide separate analytic formulas for intraband (Drude) and interband…
We develop an analytical model to describe sub-bandgap optical absorption in two-dimensional semiconducting transition metal dichalcogenide (s-TMD) nanoflakes. The material system represents an array of few-layer molybdenum disulfide…
Bismuth selenide (Bi2Se3) is a prototypical three-dimensional topological insulator whose Dirac surface states have been extensively studied theoretically and experimentally. Surprisingly little, however, is known about the energetics and…