Dear pwscf users, When I set calculation='nscf'to calculate the band structure and further the band gap , I got the valve of about 3.25eV, which agree TOO well with the experiment value (3.2eV),so even myself double the result. In order to figure out the reason, I run another one setting calculation='relax' with the other parameters the same, and I got the value of 1.64eV, which sounds quite reasonable for DFT. So I am wonder is any chance that the 'nscf' and 'relax' different so much ? And should it right or not that when we use 'nscf' the system read some information left by our former try? Thanks .
My input file is shown below &CONTROL calculation='relax', restart_mode='from_scratch', pseudo_dir='/home/tao/pseudo/', prefix='band' tstress=.true. tprnfor=.true. / &SYSTEM ibrav=6, a=4.594,c=2.958, nat=6,ntyp=2, ecutwfc=128 ,nosym=.true.,nbnd=32 Tao Junguang
