What is the unit for free energy given in file YY.fe_XX?

[AgentZero]

Dear EPW experts,

I have some questions associated with the free energy calculation in EPW.

What is the unit for free energy given in file YY.fe_XX? Is it Ry/Cell?
According to the Eq.(46) given in CPC 209, 116-133 (2016), the free energy difference
between the superconducting and normal states is proportional to the temperature T.
Does this mean that the energy difference will be zero at 0 K? Is it possible to calculate
the energy difference at 0 K?

Thanks for your time and response!

Best wishes,
Miao Gao

[roxana]

Hi,

The units for free energy is eV.

You cannot evaluate qe (46) numerically at 0 K because the temperature also enters in Z, Z_N, and Delta through the Matsubara frequencies.

Best,
Roxana