[QE-users] Dipole correction: electrostatic potential partially corrected
Giuseppe Mattioli
giuseppe.mattioli at ism.cnr.it
Fri May 1 17:58:33 CEST 2020
In other words, you have two different workfunctions on the two sides
of your slab, with two different asymptotic values of the potential
that are connected in the region indicated by Stefano and Tone by the
potential drop introduced by the dipole correction. This avoids the
ugly "capacitor effect" you experiment when you don't apply the
correction (the red curve in your plot).
Best
Giuseppe
Quoting Stefano de Gironcoli <degironc at sissa.it>:
> I think the code does what you ask for
>
> it set the dipole double layer stating al 95% (emaxpos = 0.95) of
> you cell extending for 5% up to 100% (eopreg = 0.05 )
>
> the slope from 95% to 100$% is just the internal potential drop in
> the double layer...
>
> stefano
>
> On 01/05/20 16:57, Pacome NGUIMEYA wrote:
>> Dear QE users,
>>
>> I generated a (1x1) surface slab ( with 20-angstroms vacuum) of the
>> (001) surface using a 5-layer slab model.
>> I included the dipole correction to cancel the artificial field as
>> my slab is asymmetric.
>>
>> As you can see in the picture here attached, the correction did not
>> work on both sides. In fact, I got a perfectly
>> flat potential in the vacuum region to the left of the slab but not
>> to the right.
>>
>> I tried different values for emaxpos and eopreg following the
>> example on this blog
>> https://christoph-wolf.at/2018/05/02/dipole-correction-in-quantum-espresso/, but only those in the input file below could give something close to the expected
>> result.
>>
>> PS: My slab is centered at the center of the cell.
>>
>> Can you please advise how I can get this fixed?
>>
>> Thanks in advance for your help
>>
>> &CONTROL
>> calculation = 'scf',
>> prefix = 'TaAs',
>> restart_mode = 'from_scratch',
>> pseudo_dir = './',
>> outdir = './',
>> etot_conv_thr = 1.0e-5,
>> wf_collect = .true.,
>> verbosity = 'high',
>> tefield = .true.,
>> dipfield = .true.
>> /
>> &SYSTEM
>> ibrav = 0,
>> nat = 40,
>> ntyp = 2,
>> ecutwfc = 60,
>> ecutrho = 480,
>> occupations = 'smearing',
>> smearing = 'm-p',
>> degauss = 0.03,
>> eamp = 0,
>> edir = 3,
>> emaxpos = 0.95,
>> eopreg = 0.05
>> /
>> &ELECTRONS
>> diagonalization = 'david',
>> mixing_mode = 'local-TF',
>> mixing_beta = 0.7,
>> conv_thr = 1.0e-6,
>> electron_maxstep = 300
>> /
>> ATOMIC_SPECIES
>> Ta 180.9480000000 Ta.pbe-spn-kjpaw_psl.1.0.0.UPF
>> As 74.9216000000 As.pbe-n-kjpaw_psl.1.0.0.UPF
>> CELL_PARAMETERS {angstrom}
>> 3.469828240000000 0.000000000000000 0.000000000000000
>> 0.000000000000000 3.469828240000000 0.000000000000000
>> 0.000000000000000 0.000000000000000 76.718787642331264
>> ATOMIC_POSITIONS {angstrom}
>> As 0.0000000000000000 1.7349141199999991 63.3017546359999841
>> As 0.0000000000000000 1.7349141199999991 51.5641730759999888
>> As 0.0000000000000000 1.7349141199999991 39.8265915159999935
>> As 0.0000000000000000 1.7349141199999991 28.0890099560000053
>> As 0.0000000000000000 1.7349141199999991 16.3514283959999887
>> As 0.0000000000000000 0.0000000000000000 66.2361500259999900
>> As 0.0000000000000000 0.0000000000000000 54.4985684659999947
>> As 0.0000000000000000 0.0000000000000000 42.7609869059999994
>> As 0.0000000000000000 0.0000000000000000 31.0234053459999899
>> As 0.0000000000000000 0.0000000000000000 19.2858237859999946
>> As 1.7349141199999991 0.0000000000000000 57.4329638559999935
>> As 1.7349141199999991 0.0000000000000000 45.6953822959999911
>> As 1.7349141199999991 0.0000000000000000 33.9578007359999958
>> As 1.7349141199999991 0.0000000000000000 22.2202191759999934
>> As 1.7349141199999991 0.0000000000000000 10.4826376159999981
>> As 1.7349141199999991 1.7349141199999991 60.3673592459999924
>> As 1.7349141199999991 1.7349141199999991 48.6297776859999971
>> As 1.7349141199999991 1.7349141199999991 36.8921961259999875
>> As 1.7349141199999991 1.7349141199999991 25.1546145659999922
>> As 1.7349141199999991 1.7349141199999991 13.4170330059999898
>> Ta 1.7349141199999991 0.0000000000000000 62.3364794036686973
>> Ta 1.7349141199999991 0.0000000000000000 50.5988978436687091
>> Ta 1.7349141199999991 0.0000000000000000 38.8613162836686996
>> Ta 1.7349141199999991 0.0000000000000000 27.1237347236686972
>> Ta 1.7349141199999991 0.0000000000000000 15.3861531636687161
>> Ta 1.7349141199999991 1.7349141199999991 65.2708747936686962
>> Ta 1.7349141199999991 1.7349141199999991 53.5332932336687009
>> Ta 1.7349141199999991 1.7349141199999991 41.7957116736687126
>> Ta 1.7349141199999991 1.7349141199999991 30.0581301136687102
>> Ta 1.7349141199999991 1.7349141199999991 18.3205485536687149
>> Ta 0.0000000000000000 1.7349141199999991 56.4676886236687139
>> Ta 0.0000000000000000 1.7349141199999991 44.7301070636687257
>> Ta 0.0000000000000000 1.7349141199999991 32.9925255036687162
>> Ta 0.0000000000000000 1.7349141199999991 21.2549439436687280
>> Ta 0.0000000000000000 1.7349141199999991 9.5173623836687113
>> Ta 0.0000000000000000 0.0000000000000000 59.4020840136687056
>> Ta 0.0000000000000000 0.0000000000000000 47.6645024536687103
>> Ta 0.0000000000000000 0.0000000000000000 35.9269208936687150
>> Ta 0.0000000000000000 0.0000000000000000 24.1893393336687126
>> Ta 0.0000000000000000 0.0000000000000000 12.4517577736687173
>> K_POINTS {automatic}
>> 9 9 1 1 1 1
>>
>> Regards,
>> Pacome
>> Ph.D. Candidate
>> Computational Condensed Matter Physics
>> University of Cape Town (UCT), South Africa
>>
>>
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GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
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