Browsing by Subject "Black phosphorus"

Now showing 1 - 3 of 3

Open Access
Electronic and optical properties of black phosphorus doped with Au, Sn and I atoms
(Taylor and Francis, 2018) Kutlu, E.; Narin, P.; Lisesivdin, S. B.; Özbay, Ekmel
In this study, the electronic and the optical properties of monolayer black phosphorus (BP) doped with Gold (Au), Tin (Sn) and Iodine (I) atoms have been investigated by the density-functional theory (DFT) method. In the calculations, the electronic and the optical properties of monolayer BP have been substantially changed with doping. Monolayer BP has a narrow bandgap as 0.85 eV, BP doped with these atoms, results in a metallic behaviour and nearly spin gapless band gap behaviour. The dielectric constant of BP which shows anisotropic optical properties due to different edge states as zigzag and armchair has been changed with doping especially with Au.
Open Access
Gate induced monolayer behavior in twisted bilayer black phosphorus
(IOP Publishing, 2017) Sevik, C.; Wallbank, J. R.; Gülseren, O.; Peeters, F. M.; Çakir, D.
Optical and electronic properties of black phosphorus strongly depend on the number of layers and type of stacking. Using first-principles calculations within the framework of density functional theory, we investigate the electronic properties of bilayer black phosphorus with an interlayer twist angle of 90°. These calculations are complemented with a simple k p model which is able to capture most of the low energy features and is valid for arbitrary twist angles. The electronic spectrum of 90° twisted bilayer black phosphorus is found to be x-y isotropic in contrast to the monolayer. However x-y anisotropy, and a partial return to monolayer-like behavior, particularly in the valence band, can be induced by an external out-of-plane electric field. Moreover, the preferred hole effective mass can be rotated by 90° simply by changing the direction of the applied electric field. In particular, a +0.4 (-0.4) V A-1 out-of-plane electric field results in a ~60% increase in the hole effective mass along the y (x) axis and enhances the m*y /m*x (m*x /m*y) ratio as much as by a factor of 40. Our DFT and k p simulations clearly indicate that the twist angle in combination with an appropriate gate voltage is a novel way to tune the electronic and optical properties of bilayer phosphorus and it gives us a new degree of freedom to engineer the properties of black phosphorus based devices. © 2017 IOP Publishing Ltd.
Open Access
Plasmon and phonon polaritons in planar van der Waals heterostructures
(Elsevier, 2023) Hajian, Hodjat; Erçağlar, Veysel; Özbay, Ekmel
The investigation of the characteristics of plasmon polaritons and phonon polaritons in planar systems is one of the key tools in understanding the optical response of plasmonic and phononic waveguides, metamaterials, and metasurfaces. Due to the considerable research interest in the polaritonics of van der Waals (vdW) materials in recent years, we conducted a detailed study on the infrared isotropic/anisotropic polaritons in plasmonic and phononic van der Waals heterostructures.