Physics Colloquium - February 21, 2013

Thermo-induced transformations in carbon based materials: MD viewpoints

Abstract: This talk illustrates several applications of molecular dynamic simulations. These examples show MD can predict a new class of devices and provide insights for materials management at the nanoscale. First, we create and understand basic properties of a nanoelectromechanical mass-sensor based on the single graphene membrane. By exposing graphene mat to a different types and amounts of molecules within a classical MD interface, we prove that this “nanoscale ear drum” may act not only as a mass variation sensor but also as an effective information transmitter with respect to graphene-molecule interactions. We read out this information through dynamical response functions imprinted in a tunneling current. Next, we build graphene based structures in a catalyst-free fashion directly from amorphous carbon (a–C). Theoretically, using a MD driver at DFTB(density functional tight bonding) level of theory we will mimic a substrate Joule heating d induced by current through device. We will show how, under heating. a-C dust can be transformed into well-organized graphene patches and to be self-healed. Finally, we will discuss a constructive and distractive nature of knock-on damage within a high resolution transmission microscopy experimental set-up. Here again, MD based theoretical experiments help us to provide an explanation of how one can use deposited amorphous carbon to engineer graphene (making holes etc.) either for its catalyst-free fabrication or its destruction.

Stanislav Avdoshenko
School of Materials Engineering
Purdue University
Stanislav Avdoshenko

Department of Physics and Astronomy
Ball State University
Cooper Physical Science Building, room 101
Muncie, IN 47306

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