Blar i NTNU Open på forfatter "Saroka, Vasil"
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2N+4-rule and an atlas of bulk optical resonances of zigzag graphene nanoribbons
Payod, R. B.; Grassano, D.; Santos, G. N. C.; Levshov, D. I.; Pulci, O.; Saroka, Vasil (Journal article; Peer reviewed, 2020)Development of on-chip integrated carbon-based optoelectronic nanocircuits requires fast and non-invasive structural characterization of their building blocks. Recent advances in synthesis of single wall carbon nanotubes ... -
Ab initio study of absorption resonance correlations between nanotubes and nanoribbons of graphene and hexagonal boron nitride
Payod, R. B.; Saroka, Vasil (Journal article; Peer reviewed, 2019)Density functional theory calculations are performed for the electronic band structures and optical absorption spectra of the zigzag nanoribbons and armchair nanotubes of graphene and hexagonal boron nitride as well as ... -
Band gaps in jagged and straight graphene nanoribbons tunable by an external electric field
Saroka, Vasil; Batrakov, K.G.; Demin, V.A.; Chernozatonskii, L.A. (Journal article; Peer reviewed, 2015)Band gap control by an external field is useful in various optical, infrared and THz applications. However, widely tunable band gaps are still not practical due to a variety of reasons. Using the orthogonal tight-binding ... -
Edge functionalization of finite graphene nanoribbon superlattices
Abdelsalam, H.; Saroka, Vasil; Younis, W.O. (Journal article; Peer reviewed, 2019)The effect of chemical functionalization on the electronic properties of graphene nanoribbon superlattices with zigzag and armchair terminations is investigated using the density functional theory. The calculated positive ... -
Edge-modified zigzag-shaped graphene nanoribbons: structure and electronic properties
Saroka, Vasil; Batrakov, K.G.; Chernozatonskii, L.A. (Journal article; Peer reviewed, 2014)Control of the band gap of graphene nanoribbons is an important problem for the fabrication of effective radiation detectors and transducers operating in different frequency ranges. The periodic edge-modified zigzag-shaped ... -
Electro-absorption of silicene and bilayer graphene quantum dots
Abdelsalam, H.; Talaat, M.H.; Lukyanchuk, I.; Portnoi, M.E.; Saroka, Vasil (Journal article; Peer reviewed, 2016)We study numerically the optical properties of low-buckled silicene and AB-stacked bilayer graphene quantum dots subjected to an external electric field, which is normal to their surface. Within the tight-binding model, ... -
Electro-optical properties of phoshorene quantum dots
Saroka, Vasil; Lukyanchuk, I.; Portnoi, M.E.; Abdelsalam, H. (Journal article; Peer reviewed, 2017)We study electronic and optical properties of single layer phosphorene quantum dots with various shapes, sizes, and edge types (including disordered edges) subjected to an external electric field normal to the structure ... -
Electronic and adsorption properties of extended chevron and cove-edged graphene nanoribbons
Abdelsalam, H.; Saroka, Vasil; Teleb, N.; Ali, M.; Younis, W.O.; Zhang, Q. (Peer reviewed; Journal article, 2021)The electronic and adsorption properties of chevron and cove-edged graphene nanoribbons (GNRs) are studied using first principles calculations. The positive binding and adsorption energies in conjunction with the positive ... -
Exceptional points in oligomer chains
Downing, Charles Andrew; Saroka, Vasil (Peer reviewed; Journal article, 2021)Symmetry underpins our understanding of physical law. Open systems, those in contact with their environment, can provide a platform to explore parity-time symmetry. While classical parity-time symmetric systems have received ... -
Hidden correlation between absorption peaks in achiral carbon nanotubes and nanoribbons
Saroka, Vasil; Pushkarchuk, A.L.; Kuten, S.A.; Portnoi, M.E. (Journal article; Peer reviewed, 2018)In this paper we study the effect of absorption peak correlation in finite length carbonnanotubes and graphene nanoribbons. It is shown, in the orthogonalp-orbital tight-binding modelwith the nearest neighbor approximation, ... -
Interaction of hydrated metals with chemically modified hexagonal boron nitride quantum dots: wastewater treatment and water splitting
Abdelsalam, H.; Younis, W.O.; Saroka, Vasil; Teleb, N.; Yunoki, S.; Zhang, Q. (Journal article; Peer reviewed, 2020)The electronic and adsorption properties of chemically modified square hexagonal boron nitride quantum dots are investigated using density functional theory calculations. The free energy and frequency calculations show ... -
Interband transitions in narrow-gap carbon nanotubes and graphene nanoribbons
Hartmann, R.R.; Saroka, Vasil; Portnoi, M.E. (Journal article; Peer reviewed, 2019)We use the robust nearest-neighbor tight-binding approximation to study the same footing interband dipole transitions in narrow-bandgap carbon nanotubes (CNTs) and graphene nanoribbons (GNRs). It is demonstrated that ... -
Multilayer phosphorene quantum dots in an electric field: Energy levels and optical absorption
Abdelsalam, H.; Saroka, Vasil; Lukyanchuk, I.; Portnoi, M.E. (Journal article; Peer reviewed, 2018)Triangular and hexagonal multilayer phosphorene quantum dots with armchair and zigzag terminations are investigated with the orthogonal tight-binding model. The effect of increasing the number of layers is revealed. The ... -
Optical selection rules of zigzag graphene nanoribbons
Saroka, Vasil; Shuba, M.V.; Portnoi, M.E. (Journal article; Peer reviewed, 2017)We present an analytical tight-binding theory of the optical properties of graphene nanoribbons with zigzag edges. Applying the transfer matrix technique to the nearest-neighbor tight-binding Hamiltonian, we derive analytical ... -
Phosphorene quantum dot electronic properties and gas sensing
Abdelsalam, H.; Saroka, Vasil; Younis, W.O. (Journal article; Peer reviewed, 2019)Density functional theory calculations are performed on phosphorene quantum dots having different shapes and edge terminations to investigate their structure stability, electronic properties, and gas sensing ability. All ... -
Plasmon polariton deceleration in graphene structures
Batrakov, K.G.; Saroka, Vasil; Maksimenko, S.A.; Thomsen, C. (Journal article; Peer reviewed, 2012)Surface plasmon-polariton waves with low-phase speed in carbon nanostructures can be utilized for the generation of coherent terahertz radiation through the Čerenkov mechanism, the effect being especially pronounced in ... -
Stability and electronic properties of edge functionalized silicene quantum dots: A first principles study
Abdelsalam, H.; Saroka, Vasil; Ali, M.; Teleb, N.H.; Elhaes, H.; Ibrahim, M.A. (Journal article; Peer reviewed, 2019)The stability and electronic properties of hexagonal and triangular silicene quantum dots are investigated under the effect of edge passivation by different elements and molecular groups. The structures experience a ... -
Strong light-matter coupling in carbon nanotubes as a route to exciton brightening
Shahnazaryan, V. A.; Saroka, Vasil; Shelykh, I. A.; Barnes, W. l.; Portnoi, M.E. (Journal article; Peer reviewed, 2019)We show that strong light–matter coupling can be used to overcome a long-standing problem that has prevented efficient optical emission from carbon nanotubes. The luminescence from the nominally bright exciton state of ... -
Study of a New Type of Crimped-Shape Nanotubes Cut from Bilayer Graphene with the Moiré Angle Θ = 27.8°
Demin, V.A.; Artyukh, A. A.; Saroka, Vasil; Chernozatonskii, L.A. (Journal article; Peer reviewed, 2020)New quasi-one-dimensional hollow nanostructures similar to flattened nanotubes are numerically simu- lated. These nanostructures can be obtained by connecting the edges of nanoribbons cut out of twisted bilayer graphene ... -
Tunable electro-optical properties of doped chiral graphene nanoribbons
Abdelsalam, H.; Saroka, Vasil; Atta, M. M.; Younis, W.O.; Zhang, Q. (Peer reviewed; Journal article, 2021)The electro-optical properties of doped chiral graphene nanoribbons are investigated using first principles calculations. O-atoms on edges enhance edge reconstruction with strong C=C bonds that increase the binding energy ...