Arkady V Krasheninnikov

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Irradiating solids with energetic particles is usually thought to introduce disorder, normally an undesirable phenomenon. But recent experiments on electron or ion irradiation of various nanostructures demonstrate that it can have beneficial effects and that electron or ion beams may be used to tailor the structure and properties of nanosystems with high(More)
M. Huhtala,1 A. V. Krasheninnikov,2 J. Aittoniemi,1 S. J. Stuart,3 K. Nordlund,2 and K. Kaski1 1Laboratory of Computational Engineering, Helsinki University of Technology, P.O. Box 9203, 02015 HUT, Finland 2Accelerator Laboratory, P.O. Box 43, FIN-0014 University of Helsinki, Finland 3Department of Chemistry, Clemson University, Clemson, South Carolina(More)
Graphene is one of the most promising materials in nanotechnology. The electronic and mechanical properties of graphene samples with high perfection of the atomic lattice are outstanding, but structural defects, which may appear during growth or processing, deteriorate the performance of graphene-based devices. However, deviations from perfection can be(More)
Although as-grown carbon nanotubes have relatively few defects, defects can appear at the purification stage or be deliberately introduced by irradiation with energetic particles or by chemical treatment when aiming at the desired functionality. The defects, especially vacancies, give also rise to a deleterious effect – deterioration of axial mechanical(More)
Using atomistic computer simulations, we study how ion irradiation can be used to alter the morphology of a graphene monolayer, by introducing defects of specific type, and to cut graphene sheets. Based on the results of our analytical potential molecular dynamics simulations, a kinetic Monte Carlo code is developed for modeling morphological changes in a(More)
We apply a range of density-functional-theory-based methods capable of describing van der Waals interactions with weakly bonded layered solids in order to investigate their accuracy for extended systems. The methods under investigation are the local-density approximation, semi-empirical force fields, non-local van der Waals density functionals and the(More)
While crystalline two-dimensional materials have become an experimental reality during the past few years, an amorphous 2D material has not been reported before. Here, using electron irradiation we create an sp2-hybridized one-atom-thick flat carbon membrane with a random arrangement of polygons, including four-membered carbon rings. We show how the(More)
We present a density-functional-theory study of transition-metal atoms (Sc-Zn, Pt, and Au) embedded in single and double vacancies (SV and DV) in a graphene sheet. We show that for most metals, the bonding is strong and the metal-vacancy complexes exhibit interesting magnetic behavior. In particular, an Fe atom on a SV is not magnetic, while the Fe@DV(More)
Although the precise microscopic knowledge of van der Waals interactions is crucial for understanding bonding in weakly bonded layered compounds, very little quantitative information on the strength of interlayer interaction in these materials is available, either from experiments or simulations. Here, using many-body perturbation and advanced(More)
Using density-functional theory calculations, we study the stability and electronic properties of single layers of mixed transition metal dichalcogenides (TMDs), such as MoS2xSe2(1-x), which can be referred to as two-dimensional (2D) random alloys. We demonstrate that mixed MoS2/MoSe2/MoTe2 compounds are thermodynamically stable at room temperature, so that(More)