A method and results for realistic molecular dynamic simulation of hydrogenated amorphous carbon structures using a scheme consisting of a linear combination of atomic orbitals with the local-density approximation

A method for realistic molecular dynamic (MD) simulations of the chemical bonding formation in extended hydrogenated amorphous carbon (a-C:H) structures of varying density and incorporated hydrogen content is presented. Applying the Born-Oppenheimer approximation, the forces moving the atoms via MD on the potential energy surface are calculated within an approximated MD-density functional theory which uses localized basis functions. The method is shown to describe correctly the ground state configurations of Cn microclusters, CnHm hydrocarbon molecules and radicals, as well as bulk crystalline carbon. Application to dynamical structure simulation of a-C and a-C:H results in realistic metastable configurations which are characterized electronically by a well defined gap in the electronic density of states around the Fermi energy. A reasonable structure statistics is obtained and compared with fully ab initio calculations and experiments.

[1]  Car,et al.  Ab initio calculation of properties of carbon in the amorphous and liquid states. , 1990, Physical review. B, Condensed matter.

[2]  Lars Hedin,et al.  Explicit local exchange-correlation potentials , 1971 .

[3]  D. Ellis,et al.  Ab Initio Calculation of the Electronic Structure and Optical Properties of Diamond Using the Discrete Variational Method , 1971 .

[4]  P. N. Keating,et al.  Effect of Invariance Requirements on the Elastic Strain Energy of Crystals with Application to the Diamond Structure , 1966 .

[5]  E. Fromm,et al.  Computer assisted simulation and electronical properties of realistic amorphous carbon structures , 1991 .

[6]  Robertson,et al.  Electronic and atomic structure of amorphous carbon. , 1987, Physical review. B, Condensed matter.

[7]  S. Yip,et al.  Molecular dynamics simulation of hydrocarbon molecules in condensed phases. II. Benzene , 1987 .

[8]  L. Verlet.  Computer "Experiments" on Classical Fluids. I. Thermodynamical Properties of Lennard-Jones Molecules , 1967 .

[9]  Car,et al.  Unified approach for molecular dynamics and density-functional theory. , 1985, Physical review letters.

[10]  J. Tersoff,et al.  Empirical interatomic potential for carbon, with application to amorphous carbon. , 1988, Physical review letters.

[11]  K. Laasonen,et al.  Molecular dynamics using the tight-binding approximation , 1990 .

[12]  S. Louie,et al.  X-ray form factors and the electronic structure of graphite , 1982 .

[13]  G. Seifert,et al.  LCAO-Xα Calculations of Transition Metal Clusters , 1985 .

[14]  H. Ehrhardt,et al.  Characterization of the sp2 bonds network in a-C:H layers with nuclear magnetic resonance, electron energy loss spectroscopy and electron spin resonance , 1991 .

[15]  J. Angus,et al.  Dense ‘‘diamondlike’’ hydrocarbons as random covalent networks , 1988 .

[16]  William Weltner,et al.  Carbon molecules, ions, and clusters , 1989 .

[17]  R. O. Jones,et al.  Geometric and electronic structure of clusters , 1991 .

[18]  D. Brenner,et al.  Empirical potential for hydrocarbons for use in simulating the chemical vapor deposition of diamond films. , 1990, Physical review. B, Condensed matter.

[19]  Krishnan Raghavachari,et al.  Structure, stability, and fragmentation of small carbon clusters , 1987 .

[20]  David Beeman,et al.  Modeling studies of amorphous carbon , 1984 .

[21]  Tománek,et al.  Structure and bonding of small semiconductor clusters. , 1987, Physical review. B, Condensed matter.

[22]  Martin,et al.  Structural and electronic properties of amorphous carbon. , 1989, Physical review letters.

[23]  H. Eschrig,et al.  An optimized LCAO version for band structure calculations application to copper , 1978 .