code: def thermal_conductivity(self, temperature, volume):
          
          gamma = self.gruneisen_parameter(temperature, volume)
          theta_d = self.debye_temperature(volume)  # K
          theta_a = theta_d * self.natoms**(-1./3.)  # K
          prefactor = (0.849 * 3 * 4**(1./3.)) / (20. * np.pi**3)
          # kg/K^3/s^3
          prefactor = prefactor * (self.kb/self.hbar)**3 * self.avg_mass
          kappa = prefactor / (gamma**2 - 0.514 * gamma + 0.228)
          # kg/K/s^3 * Ang = (kg m/s^2)/(Ks)*1e-10
          # = N/(Ks)*1e-10 = Nm/(Kms)*1e-10 = W/K/m*1e-10
          kappa = kappa * theta_a**2 * volume**(1./3.) * 1e-10
          return kappa
docs: Eq(17) in 10.1103/PhysRevB.90.174107
  
          Args:
              temperature (float): temperature in K
              volume (float): in Ang^3
  
          Returns:
              float: thermal conductivity in W/K/m