# Tersoff parameters for various elements and mixtures # multiple entries can be added to this file, LAMMPS reads the ones it needs # these entries are in LAMMPS "metal" units: # A,B = eV; lambda1,lambda2,lambda3 = 1/Angstroms; R,D = Angstroms # other quantities are unitless # Aidan Thompson (athomps at sandia.gov) takes full blame for this # file. It specifies various potentials published by J. Tersoff for # silicon, carbon and germanium. Since Tersoff published several # different silicon potentials, I refer to them using atom types # Si(B), Si(C) and Si(D). The last two are almost almost identical but # refer to two different publications. These names should be used in # the LAMMPS command when the file is invoked. For example: # pair_coeff * * SiCGe.tersoff Si(B). The Si(D), C and Ge potentials # can be used pure silicon, pure carbon, pure germanium, binary SiC, # and binary SiGe, but not binary GeC or ternary SiGeC. LAMMPS will # generate an error if this file is used with any combination # involving C and Ge, since there are no entries for the GeC # interactions (Tersoff did not publish parameters for this # cross-interaction.) # format of a single entry (one or more lines): # element 1, element 2, element 3, ######## Re, De, Beta, S, Detat, R1, R2, Azero, Czero, Dzero ##### m, gamma, lambda3, c, d, costheta0, n, beta, lambda2, B, R, D, lambda1, A # The original Tersoff potential for Silicon, Si(B) # J. Tersoff, PRB, 37, 6991 (1988) # The later Tersoff potential for Silicon, Si(C) # J. Tersoff, PRB, 38, 9902 (1988) # The later Tersoff potential for Carbon, Silicon, and Germanium # J. Tersoff, PRB, 39, 5566 (1989) (fixed typo in value of d for Carbon) # The Si and C parameters are very close to those in SiC.tersoff C C C 1.315 6.325 1.5 1.29 0.80469 1.7 2.0 0.011304 19 2.5