Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature

J Chem Phys. 2013 Jan 28;138(4):044701. doi: 10.1063/1.4774376.

Abstract

In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-of-equilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse the Si-C(60) collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C(60) impact on the Si surface is in good agreement with our experimental findings.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Compounds, Inorganic / chemistry*
  • Molecular Dynamics Simulation*
  • Quantum Theory*
  • Silicon Compounds / chemistry*
  • Temperature*

Substances

  • Carbon Compounds, Inorganic
  • Silicon Compounds
  • silicon carbide