Dear All,
I am new to DFT and I am working on band structure calculation of my material. It's a magnetic compound (Full-Heusler Alloy) so I am using LSDA to get the spin polarised band structure. I have to find out the energy band gap in the minority (spin-down) spin band. I have got the band structure plot. My question is How to find out the energy band gap i.e. specifically the energy values corresponding to CBmax and VBmin points? I am working with Quantum Espresso version 6.4.1 on windows.
Thanks
Hello!
If you already have the spin-down band structure it's pretty straight forward, just give a "grep 'Fermi energy' nameofsystem.out" on the output file of your SCF calculation, then you can just plot the bands with the level that you found and use Gnuplot or something to get the energy levels of CBM and VBM (which you can find visually since they will be close to the Fermi level) and do their difference.
Depending on the case the QE will not give you a Fermi energy, instead you can use "grep 'highest occupied' nameofsystem.out" and it will tell you both the HOMO and LUMO levels, then again you just have to take the difference between them to find the gap.
Cheers
