lammps/examples/USER/atc/elastic/Au_elastic.mat

material Au metal
  stress  cauchy-born
    pair_style eam
    #linear
  end
  mass_density
  body_force
end

material Au_cubic metal
  stress  cubic
    c11 11020.5189657531
    c12 9575.20500303137
    c44 2709.96368010322
  end
  mass_density
  body_force
end