Hi Sumit,

To calculate the zero-bias T(E), you can either use the wavefunction-matching approach (e.g., PWCOND code) or Green's function-based method (e.g., QuantumATK, TranSIESTA...).

If u use the latter approach, once you have the Hamiltonian and overlap matrices from DFT, you can, in principle, calculate the T(E) without iterating the Green's function (i.e., equilibrium density matrix). However, in most NEGF codes, we do the Green's function iteration anyway for zero-bias because the periodic DFT solution might differ from the NEGF one.

I hope this answers your question.

Best regards,

Dongzhe