Browsing by Author "Sharma, R."

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    Electronic structure and carrier mobilities of twisted graphene helix
    (Elsevier, 2020) Thakur, R; Ahluwalia, P.K; Kumar, A; Mohan, B; Sharma, R.
    Density functional theory based calculations have been carried out to investigate the effect of twisting on electronic band structures and carrier mobilities of three prototypes of armchair graphene nanoribbons (AGNRs) within the fixed boundary conditions. It is found that twisting causes a modification in the bandgap values and the overall shape of band structures. The values of longitudinal acoustic deformation potential (DP) are found to be higher than the torsional acoustic DP values. The torsional strain is also found to have a profound effect on effective mass and mobilities of given AGNRs. The hole mobility of hydrogen passivated N = 8 AGNRs is found to be comparable with the carrier mobility of intrinsic graphene. The electron mobility of N = 8 AGNRs can be further increased with fluorine passivation. The width, passivation, and extent of twisting together determine n-type or p-type behavior of AGNRs. Fluorine passivated AGNRs are predicted to be potential candidates for mechanical and high-frequency switching. Our results suggest that twisting of AGNRs can be an effective mean for tuning their band structure and carrier mobility for applications in high-speed switching devices. 2020 Elsevier B.V.
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    Strain controlled electronic and transport properties of Si-C atomic wire
    (American Institute of Physics, 2019) Thakur, R; Kumar, Ashok; Ahluwalia, P.K; Sharma, R.
    An ab-initio Density functional calculations and Non-equilibrium approach have been used to study the effect of positive strain on the equilibrium geometry, electronic structure and transmission function of Si-C bi atomic wire. In the absence of strain, Si-C bi-atomic wire is found to be semi conducting. The equilibrium electronic structure of these nanowires is shown to change drastically on applying strain. The Si-C bi-atomic wire has wide zigzag (WZ) structure GM and has a direct band gap of 0.7eV and remains direct on applying small strain up to ϵ ∼3.1%. At the strain value of ϵ ∼3.1% the band gap widen up to 1.77eV, and becomes indirect on further increasing the strain values. We observed that at the lower bias the conductance does depend on the strain applied on the wire. From density of states we have found that the strain value of ϵ ∼3.1% offers maximum band gap value up to the ∼1.55eV bias applied. At equilibrium state the transmission through Si bands is observed slightly more, and indicates the holes tunneling through device. Application of strain provides channels for electrons tunneling. © 2019 Author(s).