Parameters: broadening (PhysicalQuantity of type energy or temperature) – The broadening of the distribution.
Use the Gaussian smearing occupation function with a broadening of 0.1 eV on an LCAOCalculator:
numerical_accuracy_parameters = NumericalAccuracyParameters( occupation_method=GaussianSmearing(0.1*eV)) calculator = LCAOCalculator(numerical_accuracy_parameters=numerical_accuracy_parameters)
For comparison of different occupation methods and suggestions for which one to choose, see Occupation Methods.
In the Gaussian smearing scheme [FH83] one replaces the delta function in the density of states by a Gaussian distribution:
where \(\sigma\) is the broadening. This means that the integer occupation numbers are replaced by fractional occupations given by the distribution
where \(\epsilon\) is the energy of the state and \(\mu\) is the Fermi level.
In the Gaussian smearing scheme the generalized entropy is given by
The total energy at zero broadening can be estimated by adding the correction given by
|[FH83]||C. -L. Fu and K. -M. Ho. First-principles calculation of the equilibrium ground-state properties of transition metals: Applications to Nb and Mo. Phys. Rev. B, 28(10):5480–5486, November 1983. doi:10.1103/PhysRevB.28.5480.|