<div dir="ltr"><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000">Dear QE users,<br><br>I generated a (1x1) surface slab ( with 20-angstroms vacuum) of the (001) surface using a 5-layer slab model. </div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000">I included the dipole correction to cancel the artificial field as my slab is asymmetric. </div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000"><br>As you can see in the picture here attached, the correction did not work on both sides. In fact, I got a perfectly </div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000">flat potential in the vacuum region to the left of the slab but not to the right.<br><br>I tried different values for emaxpos and eopreg following the example on this blog <a href="https://christoph-wolf.at/2018/05/02/dipole-correction-in-quantum-espresso/">https://christoph-wolf.at/2018/05/02/dipole-correction-in-quantum-espresso/</a>, but only those in the input file below could give something close to the expected result.<br><br>PS: My slab is centered at the center of the cell.<br><br>Can you please advise how I can get this fixed?<br><br>Thanks in advance for your help<br><br></div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000">&CONTROL<br>                 calculation = 'scf',<br>                      prefix = 'TaAs',<br>                restart_mode = 'from_scratch',<br>                  pseudo_dir = './',<br>                      outdir = './',    <br>               etot_conv_thr = 1.0e-5,<br>                  wf_collect = .true.,<br>                   verbosity = 'high',<br>                     tefield = .true.,<br>                    dipfield = .true.<br>/<br>&SYSTEM<br>                       ibrav = 0,<br>                         nat = 40,<br>                        ntyp = 2,<br>                     ecutwfc = 60,<br>                     ecutrho = 480,<br>                 occupations = 'smearing',<br>                    smearing = 'm-p',<br>                     degauss = 0.03,<br>                        eamp = 0,<br>                        edir = 3,<br>                     emaxpos = 0.95,   <br>                      eopreg = 0.05    <br>/<br>&ELECTRONS<br>             diagonalization = 'david',<br>                 mixing_mode = 'local-TF',<br>                 mixing_beta = 0.7,<br>                    conv_thr = 1.0e-6,<br>            electron_maxstep = 300<br>/<br>ATOMIC_SPECIES<br> Ta  180.9480000000    Ta.pbe-spn-kjpaw_psl.1.0.0.UPF <br> As   74.9216000000    As.pbe-n-kjpaw_psl.1.0.0.UPF <br>CELL_PARAMETERS {angstrom}<br> 3.469828240000000       0.000000000000000       0.000000000000000<br> 0.000000000000000       3.469828240000000       0.000000000000000<br> 0.000000000000000       0.000000000000000      76.718787642331264<br>ATOMIC_POSITIONS {angstrom}<br>  As  0.0000000000000000  1.7349141199999991  63.3017546359999841<br>  As  0.0000000000000000  1.7349141199999991  51.5641730759999888<br>  As  0.0000000000000000  1.7349141199999991  39.8265915159999935<br>  As  0.0000000000000000  1.7349141199999991  28.0890099560000053<br>  As  0.0000000000000000  1.7349141199999991  16.3514283959999887<br>  As  0.0000000000000000  0.0000000000000000  66.2361500259999900<br>  As  0.0000000000000000  0.0000000000000000  54.4985684659999947<br>  As  0.0000000000000000  0.0000000000000000  42.7609869059999994<br>  As  0.0000000000000000  0.0000000000000000  31.0234053459999899<br>  As  0.0000000000000000  0.0000000000000000  19.2858237859999946<br>  As  1.7349141199999991  0.0000000000000000  57.4329638559999935<br>  As  1.7349141199999991  0.0000000000000000  45.6953822959999911<br>  As  1.7349141199999991  0.0000000000000000  33.9578007359999958<br>  As  1.7349141199999991  0.0000000000000000  22.2202191759999934<br>  As  1.7349141199999991  0.0000000000000000  10.4826376159999981<br>  As  1.7349141199999991  1.7349141199999991  60.3673592459999924<br>  As  1.7349141199999991  1.7349141199999991  48.6297776859999971<br>  As  1.7349141199999991  1.7349141199999991  36.8921961259999875<br>  As  1.7349141199999991  1.7349141199999991  25.1546145659999922<br>  As  1.7349141199999991  1.7349141199999991  13.4170330059999898<br>  Ta  1.7349141199999991  0.0000000000000000  62.3364794036686973<br>  Ta  1.7349141199999991  0.0000000000000000  50.5988978436687091<br>  Ta  1.7349141199999991  0.0000000000000000  38.8613162836686996<br>  Ta  1.7349141199999991  0.0000000000000000  27.1237347236686972<br>  Ta  1.7349141199999991  0.0000000000000000  15.3861531636687161<br>  Ta  1.7349141199999991  1.7349141199999991  65.2708747936686962<br>  Ta  1.7349141199999991  1.7349141199999991  53.5332932336687009<br>  Ta  1.7349141199999991  1.7349141199999991  41.7957116736687126<br>  Ta  1.7349141199999991  1.7349141199999991  30.0581301136687102<br>  Ta  1.7349141199999991  1.7349141199999991  18.3205485536687149<br>  Ta  0.0000000000000000  1.7349141199999991  56.4676886236687139<br>  Ta  0.0000000000000000  1.7349141199999991  44.7301070636687257<br>  Ta  0.0000000000000000  1.7349141199999991  32.9925255036687162<br>  Ta  0.0000000000000000  1.7349141199999991  21.2549439436687280<br>  Ta  0.0000000000000000  1.7349141199999991   9.5173623836687113<br>  Ta  0.0000000000000000  0.0000000000000000  59.4020840136687056<br>  Ta  0.0000000000000000  0.0000000000000000  47.6645024536687103<br>  Ta  0.0000000000000000  0.0000000000000000  35.9269208936687150<br>  Ta  0.0000000000000000  0.0000000000000000  24.1893393336687126<br>  Ta  0.0000000000000000  0.0000000000000000  12.4517577736687173<br>K_POINTS {automatic}<br> 9 9 1  1 1 1<br></div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000"><br></div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000"><div class="gmail_default">Regards,<br>Pacome</div><div class="gmail_default"><div style="font-size:12.8px"><font color="#073763" face="georgia, serif">Ph.D. Candidate</font></div><div style="font-size:12.8px"><font color="#073763" face="georgia, serif">Computational Condensed Matter Physics</font></div><div style="font-size:12.8px"><font color="#073763" face="georgia, serif">University of Cape Town (UCT), South Africa</font></div></div></div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;color:#000000"><br></div></div>