def scale_kappa_QEPWtoSI(temp, volume, timestep):
    """
    Conversion factor for the thermal conductivity from Quantum Espresso PW/HARTREE-HEATCURRENT units to SI units.
    INPUT:
    temp      =  temperature [ K ]
    volume    =  cell volume [ A^3 ]
    timestep  =  integration time step [ fs ]
    """
    kB = 1.3806504
    NA = 6.02214
    massunit = 1.660538921
    charge = 1.6021765
    J_PWtoMETAL = 1.0 / 6.719329152e-06
    return (charge / temp
        ) ** 2 / kB / volume * timestep * 10000.0 * J_PWtoMETAL ** 2
