Dear Dr. Thomas Brumme, Thank you again. I never forget this :)
2015-11-20 16:51 GMT+02:00 Thomas Brumme <[email protected]>: > Dear Bahadır, > > the input file seems to be OK. Nevertheless, you always have to test in > the end > that no charge is spilling into the vacuum because the sawtooth function is > creating an artificial potential minimum. Do this by plotting to total > potential > (pp.x, plot_num=1) for example as 3D data file and using average.x to > average > over the in-plane directions. If charge is spilling the potential is not > linear in the > vacuum region or shows other weird behavior. In this case you have to > reduce > the vacuum region in order to reduce the depth of the artificial minimum. > This > on the other hand can lead (for too large electric fields) to a vacuum > region > which is too small, i.e., leading to interactions between the repeated > slabs. > > The wrong gap you get can be due to anything - your initial input file was > just > wrong. The sawtooth within the slab itself is an unphysical situation. > > Regards > > Thomas > > > P.S.: You're using an ultrasoft pseudopotential. In such cases ecutrho > needs to > be larger than just 4 times ecutwfc. More like 10 times... Which is also > stated in > the documentation... > > > On 11/20/2015 03:27 PM, Bahadır salmankurt wrote: > > Dear Dr. Thomas Brumme, > > Thank you for clear explanation. > > And also I have changed my input file. now, Is everything ok? > > **** > &control > calculation='scf' > restart_mode='from_scratch', > prefix='As', > tstress = .true. > tprnfor = .true. > pseudo_dir ='/home/hakan/tubitak/espresso-5.2.0/pseudo/', > outdir='/home/hakan/tubitak/As/efield/out/', > ! etot_conv_thr = 1.0E-4, > ! forc_conv_thr = 1.0D-3, > wf_collect=.true., > ! verbosity='high', > tefield=.true. > *dipfield=.true.* > / > &system > nbnd=10, > ibrav=0,celldm(1)=1.8897, > nat= 2, ntyp=1, > ecutwfc =30.0, > ecutrho=120, > * emaxpos=0.95,* > eopreg=0.10, > edir = 3, > eamp = 0.0105, > / > ... > > **** > > By the way, the difference is that , when E field was applied under 5.00 > V/nm ( eamp = 0.0097 au) E field in prb paper which I shared , the band > gap became about 0.80 eV. But I find this band gap under 10.5 V/nm > (eamp=0.0205 au) E field ( I have used new input data). > > what does the reason such a difference happen? > > Thank you again.. > > > -- > Dr. rer. nat. Thomas Brumme > Max Planck Institute for the Structure and Dynamics of Matter > Luruper Chaussee 149 > 22761 Hamburg > > Tel: +49 (0)40 8998 6557 > > email: [email protected] > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- Bahadır SALMANKURT PhD student Sakarya University, TURKEY
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