Ashwin Ramasubramaniam

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We show that edge stresses introduce intrinsic ripples in freestanding graphene sheets even in the absence of any thermal effects. Compressive edge stresses along zigzag and armchair edges of the sheet cause out-of-plane warping to attain several degenerate mode shapes. Based on elastic plate theory, we identify scaling laws for the amplitude and(More)
We show that the decay of sinusoidal ripples on crystal surfaces, where mass transport is limited by the attachment and detachment of atoms at the step edges, is remarkably different from the decay behavior that has been reported until now. Unlike the decreasing or at most constant rate of amplitude decay of sinusoidal profiles observed in earlier work, we(More)
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A multilayered composite structure formed by a random stacking of graphene oxide (GO) platelets is an attractive candidate for novel applications in nanoelectromechanical systems and paper-like composites. We employ molecular dynamics simulations with reactive force fields to elucidate the structural and mechanical properties of GO paper-like materials. We(More)
We investigate band gap tuning of bilayer graphene between hexagonal boron nitride sheets, by external electric fields. Using density functional theory, we show that the gap is continuously tunable from 0 to 0.2 eV and is robust to stacking disorder. Moreover, boron nitride sheets do not alter the fundamental response from that of free-standing bilayer(More)
We present two interatomic potentials for hydrogen in –iron based on the embedded atom method potentials for iron developed by Mendelev et al. Philos. Mag. 83, 3977 2003 and Ackland et al. J. Phys.: Condens. Matter 16, S2629 2004 . Since these latter potentials are unique among existing iron potentials in their ability to produce the same core structure for(More)
We synthesized distorted octahedral (T') molybdenum ditelluride (MoTe2) and investigated its vibrational properties with Raman spectroscopy, density functional theory, and symmetry analysis. Compared to results from the high-temperature centrosymmetric monoclinic (T'mo) phase, four new Raman bands emerge in the low-temperature orthorhombic (T'or) phase,(More)
IO N The study of the electrical properties of rubrene single crystals ( Figure 1 ) has provided a better understanding of the charge transport mechanisms in organic semiconductors while opening the doors to a new generation of high-performance electronic devices. [ 1–4 ] Despite the high charge carrier mobilities of rubrene crystals, their fragile nature(More)