Acetylenic linkage dependent electronic and optical behaviour of morphologically distinct ‘-ynes’

Jana, Susmita; Bandyopadhyay, Amitava

doi:10.1039/c9cp01914f

Cited by 41 publications

(30 citation statements)

References 82 publications

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“…The tetragonal unit cell of S-graphene is defined by the lattice vectors → =â ai and → =b bj . In this paper we have extensively used the real space renormalization group (RSRG) scheme [39][40][41][42] to compute the dispersion (E-k) relation associated with the system through tight binding Hamiltonian. In particular, we have decimated out the preferred subset of atomic sites of the original lattice to achieve a scaled version of it.…”

Section: The Rsrg Schemementioning

confidence: 99%

The topology and robustness of two Dirac cones in S-graphene: A tight binding approach

Bandyopadhyay

Datta

Jana

et al. 2020

Sci Rep

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Present work reports an elegant method to address the emergence of two Dirac cones in a non-hexagonal graphene allotrope S-graphene (SG). We have availed nearest neighbour tight binding (NNTB) model to validate the existence of two Dirac cones reported from density functional theory (DFT) computations. Besides, the real space renormalization group (RSRG) scheme clearly reveals the key reason behind the emergence of two Dirac cones associated with the given topology. Furthermore, the robustness of these Dirac cones has been explored in terms of hopping parameters. As an important note, the Fermi velocity of the SG system (vF $$\simeq $$≃ c/80) is almost 3.75 times that of the graphene. It has been observed that the Dirac cones can be easily shifted along the symmetry lines without breaking the degeneracy. We have attained two different conditions based on the sole relations of hopping parameters and on-site energies to break the degeneracy. Further, in order to perceive the topological aspect of the system we have obtained the phase diagram and Chern number of Haldane model. This exact analytical method along with the supported DFT computation will be very effective in studying the intrinsic behaviour of the Dirac materials other than graphene.

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Section: The Rsrg Schemementioning

confidence: 99%

The topology and robustness of two Dirac cones in S-graphene: A tight binding approach

Bandyopadhyay

Datta

Jana

et al. 2020

Sci Rep

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“…Recent study reveals that T-graphene finds its potential application in various fields such as in hydrogen storage, − gas sensor, , current rectification device, spintronic device, and optoelectronic device, etc. Furthermore, the role of acetylenic linkages in optical and electronic properties of T graphene is also studied . Being motivated by the above studies here, we have concentrated on planar T-graphene, which is a two-dimensional sheet composed of one sublattice in its unit cell.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the role of acetylenic linkages in optical and electronic properties of T graphene is also studied. 68 Being motivated by the above studies here, we have concentrated on planar T-graphene, which is a twodimensional sheet composed of one sublattice in its unit cell. Though planar T-graphene is not yet synthesized experimentally, but it is thermodynamically stable than graphdiyne, which is already synthesized and thus shed light on the synthesis of this material in the near future.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Investigation of Nonlinear Optical Properties of T-Graphene Quantum Dots

2020

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Using density functional theory calculations, we have analyzed nonlinear optical properties of a series of T-graphene quantum dots differing in their shape and size. Electronic polarizability and first-order and second-order hyperpolarizability of these systems are investigated and shed light on their stability and electronic properties. Negative cohesive energy shows that they are energetically stable. The effect of size and incident frequency on their nonlinear responses are comprehensively discussed. Most of the systems exhibit a strong NLO response, and it is enhanced in the presence of an external field. All these systems show absorption maximum ranging from UV to visible window. Overall, this theoretical framework highlighted the nonlinear optical properties of T-graphene quantum dots that may provide valuable information in designing potential NLO materials.

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“…Regardless, the transition is still possible due to mixed optical hybridization between s and p orbitals. [ 38 ]…”

Section: Resultsmentioning

confidence: 99%

“…At plasma frequency (

\omega _p

), the value of

\epsilon _1(\omega )

changes from negative to positive and

\epsilon _2(\omega ) &lt; 1

. [ 38 ] These frequencies represent the collective excitation of free electrons in the system. The values of plasma frequency (

\omega _p

) have been noted from Figure 4 and also summarized for parallel polarization of light in Table 2 .…”

Section: Resultsmentioning

confidence: 99%

Optical and Thermoelectric Behavior of Phagraphene with Site‐Specific B‐N Co‐Doping

Ghosh

Ghosal

Jana

2022

Advcd Theory and Sims

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Phagraphene is a theoretically predicted sp 2 hybridized, se-mimetallic allotrope of graphene. The semimetallic nature of phagraphene is robust against external strain and B-N co-doping. Being experimentally realized in a nanoribbon form, this is quite fascinating in the present scenario. In this theoretical study, optical and thermoelectric properties of phagraphene and its site-dependent B-N co-doped analogous configurations are critically investigated employing density functional theory. As a consequence of inherent rectangular symmetry and direction-dependent behavior of the structures, anisotropic optical responses are obtained. The strain-induced optical responses further confirm these observations. Different positions of the optical peaks for distinct configurations lead to an elegant way of structural identifications. The absorption spectra of the structures reveal that low-energy optical transitions take place due to p z orbitals. Besides, static dielectric constant and refractive index are enhanced for the co-doped structures. Furthermore, the thermoelectric responses of the structures are explored by adapting the semi-classical Boltzmann transport equation. Importantly, a significantly higher figure of merit has been perceived, which is quite uncommon among graphene allotropes.

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Acetylenic linkage dependent electronic and optical behaviour of morphologically distinct ‘-ynes’

Abstract: We have critically examined the key role of acetylenic linkages (–CC–) in determining the opto-electronic responses of the dynamically stable tetragonal (T) ‘-ynes’ with the help of density functional theory.

Cited by 41 publications

References 82 publications

The topology and robustness of two Dirac cones in S-graphene: A tight binding approach

The topology and robustness of two Dirac cones in S-graphene: A tight binding approach

Density Functional Theory Investigation of Nonlinear Optical Properties of T-Graphene Quantum Dots

Optical and Thermoelectric Behavior of Phagraphene with Site‐Specific B‐N Co‐Doping

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