material CNT metal
stress  linear
  modulus  0.0  
  possions_ratio 0.25
end
electric_field linear
  permittivity 1.0
end
electron_density linear
  coefficient  -1.e-2  # NOTE will not converge with +0.01, try smaller pos
  #coefficient   1.e-2  # NOTE will not converge with +0.01, try smaller pos
end
mass_density
#electron_density interpolation
#  number_of_points 3
#  0    0     1.e-4
#  1.e0 1.e-4 1.e-4
#  3.e0 3.e-4 1.e-4
#end
body_force
end