Eliashberg
Parameters for McMillan’s formula.
- elphmod.eliashberg.McMillan(nq, e, w2, g2, eps=1e-10, mustar=0.0, tetra=False, kT=0.025, f='fd', correct=False)[source]
Calculate parameters and result of McMillan’s formula.
- Parameters:
- nqint
Number of q points per dimension.
- endarray
Electron dispersion on uniform mesh. The Fermi level must be at zero.
- w2ndarray
Squared phonon frequencies for irreducible q points.
- g2ndarray
Squared electron-phonon coupling (energy to the power of three).
- epsfloat
Phonon frequencies squared below eps are set to eps; corresponding couplings are set to zero.
- mustarfloat
Coulomb pseudopotential.
- tetrabool
Calculate double Fermi-surface average and density of states using 2D tetrahedron methods? Otherwise summations over broadened delta functions are performed.
- kTfloat
Smearing temperature. Only used if tetra is
False.- ffunction
Particle distribution as a function of energy divided by kT. Only used if tetra is
False.- correctbool, default False
Apply Allen and Dynes’ strong-coupling and shape corrections?
- Returns:
- float
Effective electron-phonon coupling strength \(\lambda\).
- float
Effective phonon frequency \(\langle \omega \rangle\).
- float
Estimated critical temperature of superconductivity.
- float, optional
Second-moment average phonon energy used for shape correction.
- elphmod.eliashberg.Tc(lamda, wlog, mustar=0.1, w2nd=None, correct=False)[source]
Calculate critical temperature using McMillan’s formula.
See Eqs. (2) and (34) by Allen and Dynes, Phys. Rev. B 12, 905 (1975).
- Parameters:
- lamdafloat
Effective electron-phonon coupling strength.
- wlogfloat
Logarithmic average phonon energy in eV.
- mustarfloat
Coulomb pseudopotential.
- w2ndbool, default None
Second-moment average phonon energy used for shape correction in eV.
- correctbool, default False
Apply Allen and Dynes’ strong-coupling and, if w2nd is given, shape corrections of Eq. (34)?
- Returns:
- float
Critical temperature in kelvin.