Browsing by Author "Manju, M.S."

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Effect of pressure on the band structure of BC3
(2016) Manju, M.S.; Harikrishnan, G.; Ajith, K.M.; Valsakumar, M.C.
Density functional theory (DFT) calculations were carried out to study the effect of pressure on the band structure of two dimensional BC3 sheet. BC3 is a semiconductor at ambient conditions having a band gap of ~0.3 eV. Electronic structure calculations are carried out on BC3 at pressures of 5, 20, 50 and 100 GPa. The system shows a semiconductor - metal transition by the application of pressure without any structural transition. � 2016 Author(s).
Effect of pressure on the band structure of BC3
(American Institute of Physics Inc. subs@aip.org, 2016) Manju, M.S.; Harikrishnan, H.; Ajith, A.; Valsakumar, M.C.
Density functional theory (DFT) calculations were carried out to study the effect of pressure on the band structure of two dimensional BC3 sheet. BC3 is a semiconductor at ambient conditions having a band gap of ~0.3 eV. Electronic structure calculations are carried out on BC3 at pressures of 5, 20, 50 and 100 GPa. The system shows a semiconductor - metal transition by the application of pressure without any structural transition. Â© 2016 Author(s).
Mechanically robust, self-healing graphene like defective SiC: A prospective anode of Li-ion batteries
(Elsevier B.V., 2021) Manju, M.S.; Thomas, S.; Lee, S.U.; Ajith, K.M.
First-principles density functional theory (DFT) computations are carried out to assess the potential application of a monolayer Silicon carbide (SiC) with the presence of topological and point defects. Results show that the unstable binding of pristine SiC makes it a poor candidate for the anode material. However, the introduction of vacancy and Stone-Wales type topological defect in SiC possesses a stable Li binding property. Besides, all the defective configuration showed higher electrical conductivity, superior mechanical robustness and stable formation energy. We also observed a structural reorientation from point to topological defect with a 5-8-5 ring formation in C and Si-C bi-vacancy and a Li-mediated phenomenon in the case of Si bi-vacancy. All the configurations under consideration exhibited low open-circuit voltage (0.1 V), a low Li diffusion barrier (~0.77 eV), and a fairly high specific capacity (501 mAh/g for Stone-Wales) compared to the conventional graphite anode. Besides, the ab initio molecular dynamics calculations confirmed the thermal stability and structural integrity of the defective SiC. Based on these findings, the present study suggests that SiC with a Stone-Wales defect can be a forthcoming candidate for the anode of LIBs. © 2020 Elsevier B.V.
Strain induced anisotropic mechanical and electronic properties of 2D-SiC
(Elsevier B.V., 2018) Manju, M.S.; Ajith, K.M.; Valsakumar, M.C.
A silicene derivative of the form SiC was thoroughly investigated on its behaviour with changes in stress varying from around 140 N/m to around 20 N/m and strain from ?0.2 to 0.3. Uniaxial stress (both zigzag and armchair) brought structural changes which reduced the symmetry of the system but biaxial stress brought no change in symmetry and shape of the material. Mechanical stability of the system was maintained upto a considerable stress in both uni- and biaxial cases and the system showed anisotropic behaviour with stress variations. Electronic structural variations showed strain engineering is a convenient method to tune the band gap very effectively causing semiconducting SiC to transform to metallic one at large stresses and direct to indirect bandgap in the semiconducting phase at lower stress. Charge density analysis showed a significant ionic nature of the material in the semiconducting phase. © 2018 Elsevier Ltd
Strain-induced work function in h-BN and BCN monolayers
(Elsevier B.V., 2020) Thomas, S.; Manju, M.S.; Ajith, K.M.; Lee, S.U.; Asle Zaeem, M.
In the last decade, research activities of semiconducting two-dimensional (2D) electronic materials has received widespread attention, and the work function analysis is a significant parameter for investigating the feasible optoelectronic activity of these 2D materials. Here, we report a comparative study using ab-inito based density functional theory calculations to examine the impact of uniaxial and biaxial tensile and compressive strains on the work functions of boron nitride (h-BN) and boron carbonitride (BCN) monolayers. Unlike h-BN which has a large bandgap of 5 eV, the computed direct bandgap of BCN monolayer is 1.18 eV, which is beneficial for use in optoelectronic applications. We noticed that the calculated work function of both h-BN and BCN decreases (increases) continuously by increasing the compressive (tensile) strain irrespective of the strain directions. The observed variations in the work function in both h-BN and BCN are found to be related to the modulation of Fermi energy under compressive and tensile strains. The change in bond length between the atoms changes the total energy as a function of applied strain. Moreover, the direct bandgaps of both h-BN and BCN remain unaffected within the studied range of compressive and tensile strains, which can be beneficial for their use in photovoltaic devices. We also noticed that elastic modulus and Poisson's ratio are found to be anisotropic and decrease (increase) with the application of uniaxial tensile (compressive) strain. In addition, both h-BN and BCN possess high longitudinal and transverse wave velocities. The insight gained from this study will stimulate the research on BCN in view of relevant technological applications in the fields of nanoelectronics and optoelectronics. © 2020 Elsevier B.V.
Uniaxial stress induced band structure changes in h-SiB
(2018) Manju, M.S.; Ajith, K.M.; Valsakumar, M.C.
Uniaxial stress was applied along zigzag and armchair directions in compressive and tensile regime to see if there is any metal-semiconductor transition in SiB. Metallicity increased with increasing stress both in compression and tension in zigzag and armchair directions instead of a metal-semiconductor transition. SiB maintained energetical stability in the whole range of applied stress. � 2018 Author(s).
Uniaxial stress induced band structure changes in h-SiB
(American Institute of Physics Inc. subs@aip.org, 2018) Manju, M.S.; Ajith, K.M.; Valsakumar, M.C.
Uniaxial stress was applied along zigzag and armchair directions in compressive and tensile regime to see if there is any metal-semiconductor transition in SiB. Metallicity increased with increasing stress both in compression and tension in zigzag and armchair directions instead of a metal-semiconductor transition. SiB maintained energetical stability in the whole range of applied stress. Â© 2018 Author(s).