Tuning Electronic and Structural Properties of Triple Layers of Intercalated Graphene and Hexagonal Boron Nitride: An Ab-initio Study.

2011 ◽  
Vol 1307 ◽  
Author(s):  
Samir S. Coutinho ◽  
David L. Azevedo ◽  
Douglas S. Galvão
Keyword(s):  
Boron Nitride ◽  
Electric Field ◽  
Ab Initio ◽  
Band Gap ◽  
External Electric Field ◽  
Structural Properties ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Electronic And Structural Properties ◽  
Gap Values

ABSTRACTRecently, several experiments and theoretical studies demonstrated the possibility of tuning or modulating band gap values of nanostructures composed of bi-layer graphene, bi-layer hexagonal boron-nitride (BN) and hetero-layer combinations. These triple layers systems present several possibilities of stacking. In this work we report an ab initio (within the formalism of density functional theory (DFT)) study of structural and electronic properties of some of these stacked configurations. We observe that an applied external electric field can alter the electronic and structural properties of these systems. With the same value of the applied electric field the band gap values can be increased or decreased, depending on the layer stacking sequences. Strong geometrical deformations were observed. These results show that the application of an external electric field perpendicular to the stacked layers can effectively be used to modulate their inter-layer distances and/or their band gap values.

Density Functional Theory Study of Antioxidant Adsorption onto Single- Wall Boron Nitride Nanotubes: Design of New Antioxidant Delivery Systems

2019 ◽  
Vol 22 (7) ◽  
pp. 470-482
Author(s):  
Samereh Ghazanfary ◽  
Fatemeh Oroojalian ◽  
Rezvan Yazdian-Robati ◽  
Mehdi Dadmehr ◽  
Amirhossein Sahebkar
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Vitamin C ◽  
Electric Field ◽  
External Electric Field ◽  
Lipoic Acid ◽  
Density Functional ◽  
Cell Interaction ◽  
Boron Nitride Nanotubes ◽  
Functional Theory

Background: Boron Nitride Nanotubes (BNNTs) have recently emerged as an interesting field of study, because they could be used for the realization of developed, integrated and compact nanostructures to be formulated. BNNTs with similar surface morphology, alternating B and N atoms completely substitute for C atoms in a graphitic-like sheet with nearly no alterations in atomic spacing, with uniformity in dispersion in the solution, and readily applicable in biomedical applications with no obvious toxicity. Also demonstrating a good cell interaction and cell targeting. Aim and Objective: With a purpose of increasing the field of BNNT for drug delivery, a theoretical investigation of the interaction of Melatonin, Vitamin C, Glutathione and lipoic acid antioxidants using (9, 0) zigzag BNNTs is shown using density functional theory. Methods: The geometries corresponding to Melatonin, Vitamin C, Glutathione and lipoic acid and BNNT with different lengths were individually optimized with the DMOL3 program at the LDA/ DNP (fine) level of theory. Results: In the presence of external electric field Melatonin, Vitamin C, Glutathione and lipoic acid could be absorbed considerably on BNNT with lengths 22 and 29 Å, as the adsorption energy values in the presence of external electric field are considerably increased. Conclusion: The external electric field is an appropriate technique for adsorbing and storing antioxidants on BNNTs. Moreover, it is believed that applying the external electric field may be a proper method for controlling release rate of drugs.

scholarly journals Tipping the balance: theoretical interrogation of divergent extended heterolytic fragmentations

2020 ◽  
Vol 11 (8) ◽  
pp. 2231-2242 ◽  
Author(s):  
Croix J. Laconsay ◽  
Ka Yi Tsui ◽  
Dean J. Tantillo
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Electric Field ◽  
Ab Initio ◽  
External Electric Field ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Nbo Analysis ◽  
Functional Theory

We interrogate a type of heterolytic fragmentation called a ‘divergent fragmentation’ using density functional theory (DFT), natural bond orbital (NBO) analysis, ab initio molecular dynamics (AIMD), and external electric field (EEF) calculations.

scholarly journals Carbon-Based Band Gap Engineering in the h-BN Analytical Modeling

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1026
Author(s):  
Mohammad Taghi Ahmadi ◽  
Ahmad Razmdideh ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Tight Binding ◽  
Band Gap Energy ◽  
Specific Structure ◽  
Partial Substitution ◽  
Generalized Gradient ◽  
Complete Replacement

The absence of a band gap in graphene is a hindrance to its application in electronic devices. Alternately, the complete replacement of carbon atoms with B and N atoms in graphene structures led to the formation of hexagonal boron nitride (h-BN) and caused the opening of its gap. Now, an exciting possibility is a partial substitution of C atoms with B and N atoms in the graphene structure, which caused the formation of a boron nitride composite with specified stoichiometry. BC2N nanotubes are more stable than other triple compounds due to the existence of a maximum number of B–N and C–C bonds. This paper focused on the nearest neighbor’s tight-binding method to explore the dispersion relation of BC2N, which has no chemical bond between its carbon atoms. More specifically, the band dispersion of this specific structure and the effects of energy hopping in boron–carbon and nitrogen–carbon atoms on the band gap are studied. Besides, the band structure is achieved from density functional theory (DFT) using the generalized gradient approximations (GGA) approximation method. This calculation shows that this specific structure is semimetal, and the band gap energy is 0.167 ev.

scholarly journals Study on Electronic and Optical Properties of Graphene Oxide Under an External Electric Field From First-principles

2021 ◽  
Author(s):  
Abdehafid Najim ◽  
Omar BAJJOU ◽  
Mustapha BOULGHALLAT ◽  
Mohammed Khenfouch ◽  
Khalid Rahmani
Keyword(s):  
Optical Properties ◽  
Graphene Oxide ◽  
Electric Field ◽  
Band Gap ◽  
External Electric Field ◽  
Density Of States ◽  
Density Functional ◽  
Partial Density ◽  
Total Density ◽  
Electronic And Optical Properties

Abstract Electronic and optical properties of graphene oxide (GO), under an external electric field (Eext) applied in three directions of space (x, y, z), are investigated using the density functional theory (DFT). The application of the Eext, causes a significant modifications to the electronic and optical properties of GO material. It has change the band gap, total density of states (TDOS), partial density of states (PDOS), absorption coefficient (α), dielectric function, optical conductivity, refractive index and loss function. The band gap of GO layer increases under the effects of the Eext, applied in x and y directions. On the other hand, for z direction, the band gap decreases by the effects of the Eext. The peaks of the TDOS around the Fermi level, change by the Eext applied in (x, y, z) directions. The α peaks of the GO sheet, decreases by the Eext applied in x direction, and increases if Eext applied in y and z directions. It is found that, the electronic and optical properties of GO layer, could be affected by the effects of the Eext and by its direction of application.

Influence of Electric Field on the Mechanical Properties of Hexagonal Boron-Nitride Sheets Using ab-initio Calculations

NANO ◽  
2015 ◽  
Vol 10 (03) ◽  
pp. 1550047 ◽  
Author(s):  
R. Ansari ◽  
S. Malakpour ◽  
M. Faghihnasiri ◽  
S. Ajori
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Electric Field ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
High Sensitivity ◽  
Functional Theory ◽  
Zigzag Direction ◽  
Electric Filed ◽  
Armchair Direction

In some cases such as assembling nanodevices and nanobiosensing, the effect of electric filed on the mechanical properties of nanomaterials is important and should be taken into account. The aim of this work is to investigate the effect of electric field on the mechanical properties of hexagonal boron-nitride (h-BN) using density functional theory (DFT) calculations. The results show the high sensitivity of mechanical properties to the magnitude and direction of electric field. It is observed that imposing the electric field on the armchair direction, unlike the zigzag direction, increases the magnitude of elastic properties of h-BN especially in the case of Poisson's ratio. It is further observed that the electric field perpendicular to h-BN has a negligible effect on its mechanical properties.

Energy Band Gap Modification of Graphene Deposited on a Multilayer Hexagonal Boron Nitride Substrate

2012 ◽  
Vol 1407 ◽  
Author(s):  
Celal Yelgel ◽  
Gyaneshwar P. Srivastava
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Energy Band ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Monolayer Graphene ◽  
Stable Configuration ◽  
Equilibrium Geometry ◽  
Energy Band Gap ◽  
Electron Speed

ABSTRACTThe equilibrium geometry and electronic structure of graphene deposited on a multilayer hexagonal boron nitride (h-BN) substrate has been investigated using the density functional and pseudopotential theories. We found that the energy band gap for the interface between a monolayer graphene (MLG) and a monolayer BN (MLBN) lies between 47 and 62 meV, depending on the relative orientations of the layers. In the most energetically stable configuration the binding energy is found to be approximately 40 meV per C atom. Slightly away from the Dirac point, the dispersion curve is linear, with the electron speed almost identical to that for isolated graphene. The dispersion relation becomes reasonably quadratic for the interface between MLG and 4-layer-BN, with a relative effective mass of 0.0047. While the MLG/MLBN superlattice is metallic, the thinnest armchair nanoribbon of MLG/MLBN interface is semiconducting with a gap of 1.84 eV.

scholarly journals Ab initio theory of the negatively charged boron vacancy qubit in hexagonal boron nitride

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Viktor Ivády ◽  
Gergely Barcza ◽  
Gergő Thiering ◽  
Song Li ◽  
Hanen Hamdi ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Ab Initio ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Energy Levels ◽  
Quantum Bits ◽  
Density Matrix Renormalization ◽  
Ab Initio Theory ◽  
Optically Detected ◽  
Highly Correlated

AbstractHighly correlated orbitals coupled with phonons in two-dimension are identified for paramagnetic and optically active boron vacancy in hexagonal boron nitride by first principles methods which are responsible for recently observed optically detected magnetic resonance signal. Here, we report ab initio analysis of the correlated electronic structure of this center by density matrix renormalization group and Kohn-Sham density functional theory methods. By establishing the nature of the bright and dark states as well as the position of the energy levels, we provide a complete description of the magneto-optical properties and corresponding radiative and non-radiative routes which are responsible for the optical spin polarization and spin dependent luminescence of the defect. Our findings pave the way toward advancing the identification and characterization of room temperature quantum bits in two-dimensional solids.

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