<html>Dear Clarence,<br />An energy barrier should represent a local event, ie, not periodically repeted.<br />For these reason, the Kpoint mesh should not affect the energy barrier.<br />I conclude from your results that you have long range interactions and that your supercell is too small along xy to represent an isolated Li.<br /><br />Regards,<br /><br />Antoine Jay<br />LAAS-CNRS<br />Toulouse, France<br /><br />Le Mercredi, Mars 24, 2021 03:52 CET, LEUNG Clarence <liangxy123@hotmail.com> a écrit:<br /> <blockquote type="cite" cite="ME3P282MB1890F61B10E8629E62C9586F93639@ME3P282MB1890.AUSP282.PROD.OUTLOOK.COM"> </blockquote><meta http-equiv="Content-Type" content="text/html; "><meta name="Generator" content="Microsoft Word 15 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
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--></style><div class="WordSection1"><p class="MsoNormal"><span lang="EN-US">Dear QE users,</span></p><p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span lang="EN-US">Recently, I study on the Li ion diffusion on 2D layer surface. And I found that the K-point in neb.x significantly affects the barrier. The following figure is 5*5*1, 9*9*1 and 13*13*1,</span></p><p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span lang="EN-US"><img style="width:3.8739in;height:2.0084in" id="Picture_x0020_4" width="372" height="193" src="cid:image001.png@01D7209A.775FF9F0" /><img style="width:3.9075in;height:2.0672in" id="Picture_x0020_5" width="375" height="198" src="cid:image002.png@01D7209A.AE287B60" /></span></p><p class="MsoNormal"><span lang="EN-US"><img style="width:3.8067in;height:3.4369in" id="Picture_x0020_6" width="365" height="330" src="cid:image004.png@01D7209B.B9D0FD60" /></span></p><p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span lang="EN-US">Except point, all set are fixed as follows:</span></p><p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span lang="EN-US">BEGIN</span></p><p class="MsoNormal"><span lang="EN-US">BEGIN_PATH_INPUT</span></p><p class="MsoNormal"><span lang="EN-US">&PATH</span></p><p class="MsoNormal"><span lang="EN-US"> restart_mode = 'from_scratch'</span></p><p class="MsoNormal"><span lang="EN-US"> string_method = 'neb',</span></p><p class="MsoNormal"><span lang="EN-US"> nstep_path = 500,</span></p><p class="MsoNormal"><span lang="EN-US"> ds = 1.D0,</span></p><p class="MsoNormal"><span lang="EN-US"> opt_scheme = "broyden",</span></p><p class="MsoNormal"><span lang="EN-US"> num_of_images = 10,</span></p><p class="MsoNormal"><span lang="EN-US"> CI_scheme = "no-CI",</span></p><p class="MsoNormal"><span lang="EN-US"> path_thr = 0.05D0,</span></p><p class="MsoNormal"><span lang="EN-US">/</span></p><p class="MsoNormal"><span lang="EN-US">END_PATH_INPUT</span></p><p class="MsoNormal"><span lang="EN-US">BEGIN_ENGINE_INPUT</span></p><p class="MsoNormal"><span lang="EN-US">&CONTROL</span></p><p class="MsoNormal"><span lang="EN-US"> nstep = 200 ,</span></p><p class="MsoNormal"><span lang="EN-US"> wf_collect = .true. ,</span></p><p class="MsoNormal"><span lang="EN-US"> verbosity='low',</span></p><p class="MsoNormal"><span lang="EN-US"> max_seconds = 320000 ,</span></p><p class="MsoNormal"><span lang="EN-US"> etot_conv_thr = 3.7D-7 ,</span></p><p class="MsoNormal"><span lang="EN-US"> forc_conv_thr = 4.0D-4 ,</span></p><p class="MsoNormal"><span lang="EN-US">/</span></p><p class="MsoNormal"><span lang="EN-US">&SYSTEM</span></p><p class="MsoNormal"><span lang="EN-US"> ibrav=4,</span></p><p class="MsoNormal"><span lang="EN-US"> celldm(1)=16.8205089265d0, celldm(3)=2.8086637164d0,</span></p><p class="MsoNormal"><span lang="EN-US"> nat=28,</span></p><p class="MsoNormal"><span lang="EN-US"> ntyp=3,</span></p><p class="MsoNormal"><span lang="EN-US"> ecutwfc=60,</span></p><p class="MsoNormal"><span lang="EN-US"> ecutrho=600,</span></p><p class="MsoNormal"><span lang="EN-US"> input_dft='PBE',</span></p><p class="MsoNormal"><span lang="EN-US"> occupations='smearing',</span></p><p class="MsoNormal"><span lang="EN-US"> smearing = 'gaussian' ,</span></p><p class="MsoNormal"><span lang="EN-US"> degauss = 0.01 ,</span></p><p class="MsoNormal"><span lang="EN-US"> nspin = 2 ,</span></p><p class="MsoNormal"><span lang="EN-US"> starting_magnetization(1) = 0.5 ,</span></p><p class="MsoNormal"><span lang="EN-US"> vdw_corr = 'DFT-D3' ,</span></p><p class="MsoNormal"><span lang="EN-US">/</span></p><p class="MsoNormal"><span lang="EN-US">&ELECTRONS</span></p><p class="MsoNormal"><span lang="EN-US"> conv_thr=1d-07,</span></p><p class="MsoNormal"><span lang="EN-US"> mixing_beta=0.7d0,</span></p><p class="MsoNormal"><span lang="EN-US"> mixing_mode ='local-TF',</span></p><p class="MsoNormal"><span lang="EN-US"> electron_maxstep = 500 ,</span></p><p class="MsoNormal"><span lang="EN-US">/</span></p><p class="MsoNormal"><span lang="EN-US">&IONS</span></p><p class="MsoNormal"><span lang="EN-US">/</span></p><p class="MsoNormal"><span lang="EN-US">ATOMIC_SPECIES</span></p><p class="MsoNormal"><span lang="EN-US"> Li 6.941000d0 Li.pbe-sl-kjpaw_psl.1.0.0.UPF</span></p><p class="MsoNormal"><span lang="EN-US"> N 14.006700d0 N.pbe-n-kjpaw_psl.1.0.0.UPF</span></p><p class="MsoNormal"><span lang="EN-US"> Ti 47.867000d0 Ti.pbe-spn-kjpaw_psl.1.0.0.UPF</span></p><p class="MsoNormal"><span lang="EN-US">K_POINTS {automatic}</span></p><p class="MsoNormal"><span lang="EN-US"> <b><u><span style="color:red">1 1 1</span></u><span style="color:red"> </span></b>0 0 0</span></p><p class="MsoNormal"><span lang="EN-US">BEGIN_POSITIONS</span></p><p class="MsoNormal"><span lang="EN-US">FIRST_IMAGE</span></p><p class="MsoNormal"><span lang="EN-US">ATOMIC_POSITIONS {crystal}</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7770490991 0.2207650450 0.4526649491</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8912354588 0.1122845729 0.5447173889</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6666667383 0.0000000000 0.4995961962</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7780555528 0.5556941072 0.4517577041</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8890435897 0.4447534785 0.5440905933</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6673919617 0.3329974904 0.4979423184</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7770488498 0.8896175800 0.4526648274</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8890434165 0.7776226563 0.5440907450</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6673920333 0.6677278762 0.4979422530</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1088705771 0.2211023009 0.4510416620</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2233051542 0.1132758120 0.5420585003</span></p><p class="MsoNormal"><span lang="EN-US">N -0.0010611379 -0.0007252950 0.4979422530</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1109726480 0.5556945774 0.4517577341</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2233049049 0.4433625308 0.5420583786</span></p><p class="MsoNormal"><span lang="EN-US">N -0.0010611379 0.3329974188 0.4979422530</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1109728212 0.8886111263 0.4517575824</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2219134870 0.7776229056 0.5440906233</span></p><p class="MsoNormal"><span lang="EN-US">N 0.0000000000 0.6666667383 0.4979808302</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4455657413 0.2211020516 0.4510417837</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5543824685 0.1122843997 0.5447172372</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3336691046 -0.0007252950 0.4979422530</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4455652711 0.5577968215 0.4510418137</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5533912294 0.4433620606 0.5420583486</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3333332617 0.3333332617 0.4956870765</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4459022777 0.8896177532 0.4526649791</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5543819983 0.7754308633 0.5447172672</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3336691762 0.6677278046 0.4979421876</span></p><p class="MsoNormal"><span lang="EN-US">Li 0.3333330289 0.3333338479 0.6400903690</span></p><p class="MsoNormal"><span lang="EN-US">INTERMEDIATE_IMAGE</span></p><p class="MsoNormal"><span lang="EN-US">ATOMIC_POSITIONS {crystal}</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7789152822 0.2220836302 0.4501659003</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8888446372 0.1110228518 0.5426653048</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6673156201 -0.0006488818 0.4964052852</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7789152822 0.5568316396 0.4501659003</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8867836243 0.4433916373 0.5427300585</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6675598953 0.3337799476 0.4952771792</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7777776240 0.8888888058 0.4505257421</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8888446372 0.7778214356 0.5426653048</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6673156201 0.6679645019 0.4964052852</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1098352888 0.2220838795 0.4501657786</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2237552464 0.1118774483 0.5405467345</span></p><p class="MsoNormal"><span lang="EN-US">N -0.0012977636 -0.0006488818 0.4964052852</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1111114878 0.5555557376 0.4510371855</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2232753282 0.4433921075 0.5427300885</span></p><p class="MsoNormal"><span lang="EN-US">N 0.0001334406 0.3336001430 0.4969839949</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1098352888 0.8877513969 0.4501657786</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2232753282 0.7798828710 0.5427300885</span></p><p class="MsoNormal"><span lang="EN-US">N 0.0001334406 0.6665332977 0.4969839949</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4444451994 0.2222225935 0.4488650365</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5547895931 0.1118772751 0.5405465828</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3328866474 -0.0008932286 0.4952771138</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4445836925 0.5568321098 0.4501659303</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5547895931 0.4429119684 0.5405465828</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3328866474 0.3337798760 0.4952771138</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4445836925 0.8877515701 0.4501659303</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5556437194 0.7778216849 0.5426651831</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3330664520 0.6665332261 0.4969839295</span></p><p class="MsoNormal"><span lang="EN-US">Li 0.4444459557 0.2222229977 0.6387918156</span></p><p class="MsoNormal"><span lang="EN-US">LAST_IMAGE</span></p><p class="MsoNormal"><span lang="EN-US">ATOMIC_POSITIONS {crystal}</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7788993600 0.2211011068 0.4510426589</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8877157525 0.1122843572 0.5447186005</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6670022049 -0.0007257761 0.4979412162</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7788993600 0.5577982408 0.4510426589</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8867240759 0.4433618631 0.5420585485</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6666666667 0.3333333333 0.4956851811</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.7792359152 0.8896179514 0.4526660159</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.8877157525 0.7754310455 0.5447186005</span></p><p class="MsoNormal"><span lang="EN-US">N 0.6670022049 0.6677279810 0.4979412162</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1103825154 0.2207645516 0.4526660159</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2245690642 0.1122843572 0.5447186005</span></p><p class="MsoNormal"><span lang="EN-US">N 0.0000000000 0.0000000000 0.4995954192</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1113906330 0.5556953102 0.4517586619</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2223762417 0.4447520239 0.5440918698</span></p><p class="MsoNormal"><span lang="EN-US">N 0.0007257761 0.3329977951 0.4979412162</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.1103825154 0.8896179514 0.4526660159</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.2223762417 0.7776238680 0.5440918698</span></p><p class="MsoNormal"><span lang="EN-US">N 0.0007257761 0.6677279810 0.4979412162</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4422022260 0.2211011068 0.4510426589</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5566382465 0.1132760338 0.5420585485</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3322720190 -0.0007257761 0.4979412162</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4443051566 0.5556953102 0.4517586619</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5566382465 0.4433618631 0.5420585485</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3322720190 0.3329977951 0.4979412162</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.4443051566 0.8886098338 0.4517586619</span></p><p class="MsoNormal"><span lang="EN-US">Ti 0.5552480857 0.7776238680 0.5440918698</span></p><p class="MsoNormal"><span lang="EN-US">N 0.3333333333 0.6666666667 0.4979808492</span></p><p class="MsoNormal"><span lang="EN-US">Li 0.6666674857 0.3333338479 0.6400822952</span></p><p class="MsoNormal"><span lang="EN-US">END_POSITIONS</span></p><p class="MsoNormal"><span lang="EN-US">END_ENGINE_INPUT</span></p><p class="MsoNormal"><span lang="EN-US">END</span></p><p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span lang="EN-US">Thank you for your suggestion in advances!<o:p></o:p></span></p><p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span lang="EN-US">Best regards,<o:p></o:p></span></p><p class="MsoNormal"><span lang="EN-US">Clarence<o:p></o:p></span></p><p class="MsoNormal"><span lang="EN-US">Postdoctoral Fellow<o:p></o:p></span></p><p class="MsoNormal"><span lang="EN-US">City University of Hong Kong<o:p></o:p></span></p><p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p></div><br /><br /><br /> </html>