@article{orlikowski_mehrez_taylor_guo_wang_roland_2001, title={Resonant transmission through finite-sized carbon nanotubes}, volume={63}, ISSN={["2469-9969"]}, DOI={10.1103/physrevb.63.155412}, abstractNote={We have investigated theoretically the conductance through finite-sized carbon nanotubes coupled to featureless leads in the context of standard tight-binding models. Conduction takes place via resonant tunneling, and the resultant spectrum of peaks may be understood in terms of the band structure of the nanotubes. Specific nanotubes display both on- and off-resonance behavior as a function of nanotube length depending upon whether or not the bands cross at a nonzero k value. We have also investigated the approach to the infinite limit in detail, and, in general, find that the finite-size effects can persist out to hundreds of nanometers. Since the manipulation of nanotubes into devices is likely to induce defects, we have investigated their effects on the conduction. The effects of bending and two broad classes of defects, i.e., defect in the absence and/or presence of addimers, were considered. In general, the presence of defects leads both to a reduction and shifting of the resonant peaks at the Fermi level. However, in the infinite limit, low concentrations of defects have only a relatively modest effect on the transport properties. Finally, we have investigated the effects of an externally imposed magnetic field oriented perpendicular to the nanotube axis. The magnetic field shifts the levels, thereby turning on- and off-resonant devices into each other. All of the effects discussed here are testable experimentally.}, number={15}, journal={PHYSICAL REVIEW B}, author={Orlikowski, D and Mehrez, H and Taylor, J and Guo, H and Wang, J and Roland, C}, year={2001}, month={Apr} }
 @article{nardelli_fattebert_orlikowski_roland_zhao_bernholc_2000, title={Mechanical properties, defects and electronic behavior of carbon nanotubes}, volume={38}, ISSN={["1873-3891"]}, DOI={10.1016/S0008-6223(99)00291-2}, abstractNote={Using state-of-the-art classical and quantum simulations, we have studied the mechanical and electronic response of carbon nanotubes to external deformations, such as strain and bending. In strained nanotubes the spontaneous formation of double pentagon–heptagon defect pairs is observed. Tubes containing these defects are energetically preferred to uniformly stretched tubes at strains greater than 5%. These defects act as nucleation centers for the formation of dislocations in the originally ideal graphitic network and constitute the onset of further deformations of the carbon nanotube. In particular, plastic or brittle behaviors can occur depending upon the external conditions and tube symmetry. We have also investigated the effects that the presence of addimers has on strained carbon nanotubes. The main result is the formation of a new class of defects that wrap themselves about the circumference of the nanotube. These defects are shown to modify the geometrical structure and to induce the formation of nanotube-based quantum dots. Finally, we computed transport properties for various ideal and mechanically deformed carbon nanotubes. High defect densities are shown to greatly affect transport in individual nanotubes, while small diameter bent armchair nanotubes mantam thier basic electrical properties even in presence of large deformations with no defects involved.}, number={11-12}, journal={CARBON}, author={Nardelli, MB and Fattebert, JL and Orlikowski, D and Roland, C and Zhao, Q and Bernholc, J}, year={2000}, pages={1703–1711} }
 @article{orlikowski_nardelli_bernholc_roland_2000, title={Theoretical STM signatures and transport properties of native defects in carbon nanotubes}, volume={61}, ISSN={["2469-9969"]}, DOI={10.1103/physrevb.61.14194}, abstractNote={We have investigated theoretically the STM images and conductance signatures of defective carbon nanotubes. The defects considered are those that form on nanotubes under tension, both in the absence and presence of additional carbon atoms. The most prominent features observed in the STM images are a set of bright rings, whose positions correlate with the location of the pentagons within the defect. These features are useful, as they enable the ready identification of many of the defects. By contrast, most of the defects have only a relatively modest effect on the transport properties of the nanotubes. While there is a general decrease in the conductance of the nanotube due to scattering effects, there appears to be no unique feature that can be associated with any of the defects investigated. This unfortunately precludes the use of transport measurements as a means of defect identification. The STM images and conductances of nanotube heterojunctions, as well as tubes under different bias voltages, have also been explored.}, number={20}, journal={PHYSICAL REVIEW B}, author={Orlikowski, D and Nardelli, MB and Bernholc, J and Roland, C}, year={2000}, month={May}, pages={14194–14203} }
 @article{orlikowski_sagui_somoza_roland_2000, title={Two- and three-dimensional simulations of the phase separation of elastically coherent binary alloys subject to external stresses}, volume={62}, ISSN={["2469-9969"]}, DOI={10.1103/physrevb.62.3160}, abstractNote={The effects of externally imposed stresses on the phase separation process of elastically coherent binary-alloy systems were investigated numerically with large-scale Langevin simulations. Both two- and three-dimensional systems were considered. The intrinsic crystallographic symmetries of the system compete with the external strains in the determination of both the shapes and the orientation of the precipitates. These can go all the way from the configurations predicted by a stress-free equilibrium criterion at small stresses, to lamellar and cylindrical configurations (or stripe configurations in two dimensions) at high stresses. Between these two extremes, there are new shapes and a continuous spectrum of orientation angles. This competition can also induce late-time, large-scale splitting of the domains. The stress effect is larger when the precipitates form the majority phase, and considerably smaller when they are in the minority.}, number={5}, journal={PHYSICAL REVIEW B}, author={Orlikowski, D and Sagui, C and Somoza, AM and Roland, C}, year={2000}, month={Aug}, pages={3160–3168} }
 @article{orlikowski_nardelli_bernholc_roland_1999, title={Ad-dimers on strained carbon nanotubes: A new route for quantum dot formation?}, volume={83}, ISSN={["0031-9007"]}, DOI={10.1103/PhysRevLett.83.4132}, abstractNote={Among the many remarkable properties of single-walled carbon nanotubes, it is their mechanical and electronic properties that stand out [1]. The excellent resistance of carbon nanotubes to bending [2 –7] should lead to future applications of the tubes as a high-strength, lightweight material. Turning to their electronic properties, we find that, at ambient temperatures, single-walled carbon nanotubes may be either metallic or semiconducting, depending upon their helicity [8– 12]. It has been shown [13] that tubes with different helicities may be joined together with one or more pentagon-heptagon (5-7) defects to form different electronic heterojunctions, thereby opening up the intriguing possibility of forming all-carbon based microelectronic devices [14,15]. Some of these remarkable theoretical predictions have recently been confirmed by scanning tunneling microscopy (STM) experiments [16]. However, if the dream of producing an all-carbon-based microelectronics is ever to be realized, then different methods will be needed to produce a variety of devices. Here, we present the results of a large-scale study of the mechanical transformations of strained nanotubes in the presence of ad-dimers and show that this combination may well turn out to be a natural route for the formation of all-carbon nanotube-based quantum dots. Ad-dimers are likely to be present in small amounts on as-grown carbon nanotubes, or they may be deposited there with a STM tip or other methods. The formation of quantum dots with ad-dimers is particularly favorable for the n ,0 zigzag tubes. Specifically, we show that ad-dimers induce plastic behavior on tubes that are otherwise brittle. Before discussing the simulations, we briefly review the}, number={20}, journal={PHYSICAL REVIEW LETTERS}, author={Orlikowski, D and Nardelli, MB and Bernholc, J and Roland, C}, year={1999}, month={Nov}, pages={4132–4135} }
 @article{orlikowski_sagui_somoza_roland_1999, title={Large-scale simulations of phase separation of elastically coherent binary alloy systems}, volume={59}, ISSN={["2469-9969"]}, DOI={10.1103/physrevb.59.8646}, abstractNote={The effects of long-range elastic fields on the phase separation process of both two- and three-dimensional binary alloy systems was investigated with large-scale Langevin simulations. The elastic effects incorporated in the model are the result of anisotropy and dilational misfits introduced via inhomogeneities in the elastic constants of the constituents. The domain morphology obtained is readily understandable in terms of selection criteria for the shape and/or orientation of the domains based on the different shear moduli that are present in the system. Furthermore, the coarsening behavior of the domains is discussed in terms of the generated chemical potential barriers surrounding the precipitates. Other aspects of the coarsening process such as dynamic scaling of the correlation functions and local inverse coarsening are also discussed.}, number={13}, journal={PHYSICAL REVIEW B}, author={Orlikowski, D and Sagui, C and Somoza, A and Roland, C}, year={1999}, month={Apr}, pages={8646–8659} }