Wannier function analysis of tetrahedral amorphous networks

Abstract Car–Parrinello molecular dynamics has been used to synthesise and characterise tetrahedral amorphous carbon (ta-C) and hydrogenated silicon carbide (a-SiC:H). Using maximally-localized Wannier functions we are able to unambiguously label bonding in the networks. These functions are considerably more reliable than the coordination sphere approach, where bonding statistics may strongly depend on the particular choice of radius. Application of the local spin density approximation to ta-C improves the agreement with experiment, giving an improved sp3 fraction and a small proportion of unpaired spins. The chemical order of stoichiometric a-SiC:H alloys is found to increase upon hydrogenation, a dramatic initial rise being followed by a gradual decrease with further addition of hydrogen.

[1]  Sven Ulrich,et al.  Stress-induced formation of high-density amorphous carbon thin films , 1997 .

[2]  N. Marzari,et al.  Maximally localized generalized Wannier functions for composite energy bands , 1997, cond-mat/9707145.

[3]  Modelling diamond-like carbon with the environment-dependent interaction potential , 2002 .

[4]  Teter,et al.  Separable dual-space Gaussian pseudopotentials. , 1996, Physical review. B, Condensed matter.

[5]  K. Ho,et al.  Structural trends in amorphous carbon , 1994 .

[6]  S. J. Collocott,et al.  MAGNETIC AND SPIN PROPERTIES OF TETRAHEDRAL AMORPHOUS-CARBON , 1995 .

[7]  A. Becke,et al.  Density-functional exchange-energy approximation with correct asymptotic behavior. , 1988, Physical review. A, General physics.

[8]  Maximally-localized Wannier functions for disordered systems: application to amorphous silicon , 1998, cond-mat/9804019.

[9]  Michele Parrinello,et al.  General and efficient algorithms for obtaining maximally localized Wannier functions , 2000 .

[10]  K. Albe,et al.  Molecular-dynamics simulations of steady-state growth of ion-deposited tetrahedral amorphous carbon films , 2000 .

[11]  P. Hohenberg,et al.  Inhomogeneous Electron Gas , 1964 .

[12]  David Alan Drabold,et al.  Theory of diamondlike amorphous carbon. , 1994, Physical review. B, Condensed matter.

[13]  A. Sproul,et al.  Structural study of hydrogenated amorphous silicon–carbon alloys , 1986 .

[14]  W. Kohn,et al.  Self-Consistent Equations Including Exchange and Correlation Effects , 1965 .

[15]  C. J. Umrigar,et al.  A critical assessment of the Self-Interaction Corrected Local Density Functional method and its algorithmic implementation , 1996 .

[16]  W. Howells,et al.  The Effect Of Hydrogen Dilution On The Interatomic Bonding Of Amorphous Hydrogenated Silicon - Carbon , 1994 .

[17]  D. Mckenzie,et al.  Ab initio simulations of the structure of amorphous carbon , 2000 .

[18]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[19]  Reimer,et al.  Structure and properties of amorphous hydrogenated silicon carbide. , 1987, Physical review. B, Condensed matter.

[20]  Seifert,et al.  Construction of tight-binding-like potentials on the basis of density-functional theory: Application to carbon. , 1995, Physical review. B, Condensed matter.

[21]  Wannier function analysis of silicon–carbon alloys , 2003 .

[22]  D. Mckenzie.  Tetrahedral bonding in amorphous carbon , 1996 .

[23]  Mckenzie,et al.  Ab initio simulations of tetrahedral amorphous carbon. , 1996, Physical review. B, Condensed matter.

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