Abstractsold‎ > ‎

Arkady Krasheninnikov: Tailoring the atomic and electronic structure of 2D carbon and boron-nitride materials by electron and ion beams

posted 12 Jul 2011, 14:46 by info admin
Recent experiments (see Refs. [1,2] for an overview) on ion and electron bombardment of nanostructures demonstrate that irradiation can have beneficial effects on such targets and that electron or ion beams can serve as tools to change the morphology and tailor mechanical, electronic and even magnetic properties of various nanostructured materials.

We systematically study irradiation effects in nanomaterilas, including two-dimensional (2D) systems like graphene and hexagonal boron-nitride (h-BN) sheets. By employing various atomistic models ranging from empirical potentials to time-dependent density functional theory we simulate collisions of energetic particles with 2D nanostructures and calculate the properties of the systems with the irradiation-induced defect.

In this talk, our latest theoretical results on the response of graphene [3,4] and h-BN [5] to irradiation will be presented, combined with the experimental results obtained in collaboration with several groups. The electronic structure of defected graphene sheets with adsorbed transition metal atoms will be discussed, and possible avenues for tailoring the electronic and magnetic structure of graphene by irradiation-induced defects and impurities will be introduced. The effects of electron irradiation on boron-nitride sheets and nanotubes will also be touched upon. Finally, we will discuss [6] how electron irradiation and electron beam-assisted deposition can be used for engineering hybrid BN-C nanosystems by substituting B and N atoms with carbon with a high spatial resolution.

[1] A. V. Krasheninnikov and F. Banhart, Nature Materials, 6 (2007) 723.
[2] A.V. Krasheninnikov and K. Nordlund, Appl. Phys. Rev., 107 (2010) 071301.
[3] J. Kotakoski, A. V. Krasheninnikov, U, Kaiser, and J. Meyer, Phys. Rev. Lett. 106 (2011) 105505.
[4] J. Kotakoski, J. C. Meyer, S. Kurasch, D. Santos-Cottin, U. Kaiser and A. V. Krasheninnikov, Phys. Rev. B 83 (2011) 245420.  
[5] J. Kotakoski, C. H. Jin, O. Lehtinen, K. Suenaga, and A. V. Krasheninnikov, Phys. Rev. B 82 (2010) 113404.
[6] N. Berseneva, A. V. Krasheninnikov, and R.M. Nieminen, Phys. Rev. Lett. (2011) in press.

Arkady Krasheninnikov, Department of Physics, University of Helsinki, Finland, Department of Applied Physics, Aalto University, Finland. arkady.krasheninnikov@helsinki.fi. 
Docent degree from University of Helsinki, 2005. Senior scientist, Accelerator Laboratory, University of Helsinki and Researcher, Laboratory of Physics, Helsinki University of Technology. Ph.D. Degree in Physics (Solid State Physics), Moscow State Engineering Physics Institute, 1995.  Thesis "The effect of defects and nonmagnetic impurities on the superconducting correlations with s- and d- symmetry in high-temperature superconductors". 15 years of experience in Computer simulations in irradiation effects in solids; Electronic structure calculations at the DFT and tight-binding levels of theory; Empirical-potential atomistic simulations;  Effects of ion irradiation on carbon nanostructures; Simulation of scanning tunneling microscopy (STM) images; theory of STM; Theoretical investigation of semiconductor nanosystems, including resonant-tunneling structures, quantumcascade lasers and nano-scale quantum devices for nanocomputing; Quantum computing in solid-state systems;  Theoretical study and computer modeling of the influence of radiation defects and impurities on both normal and superconducting properties of superconductors; Strongly correlated systems; exact diagonalization of finite clusters