EPW Forum

Dear developers,

I am trying to calculate the formation energy of hole polarons in 3C-SiC with coarse k/q grids (e.g, nkf1=nkf2=nqf3=6x6x6). When setting `fermi_energy` close to Evbm, we get a formation energy of about -14.7842720 eV, but without setting `fermi_energy`, we get a value of -0.0011676 eV. I don't know which is correct.

Best,
Qiaolin

Hi Qiaolin,

The polaron module does not support reading fermi energy from input, and the current implementation will give some silent bugs if you set fermi_energy in the input file. So you should trust the value that you got without setting fermi_energy. This bug will be fixed a near future release.

Best,
Zhenbang

Dear Zhenbang,

Thanks for your reply.

Without setting `fermi_energy`, I have another question . If I want to investigate the formation of hole polarons, I wander if `num_wann` should contain only the number of valence bands. I noticed that the obtained Wannier functions correspond only to the valence bands, or to both the valence and conduction bands, and they give different results.

Best,
Qiaolin