docs: def meff_e_Gamma(self, **kwargs):
          '''
          Returns the electron effective mass in the Gamma-valley
          calculated from Eg_Gamma(T), Delta_SO, Ep and F.
          
          Interpolation of Eg_Gamma(T), Delta_SO, Ep and F, and
          then calculation of meff_e_Gamma is recommended for alloys.
          '''
          Eg = self.Eg_Gamma(**kwargs)
          Delta_SO = self.Delta_SO(**kwargs)
          Ep = self.Ep(**kwargs)
          F = self.F(**kwargs)
          return 1./((1.+2.*F)+(Ep*(Eg+2.*Delta_SO/3.))/(Eg*(Eg+Delta_SO)))