Ge bandgap calculations in CP2K using PBE0

anurag vohra anu... at gmail.com
Sun Feb 11 11:48:39 UTC 2018


Hi,

Any pointers please? Why I am getting underestimation of bandgap in case of 
Ge using PBE0? I tried the same for Silicon (both with and without OT using 
ADDED MOS). I get correct results and right opening of bandgap around 1.2eV 
for 2A cut-off radius.  

Regards,
Anurag

On Monday, 29 January 2018 11:56:00 UTC+1, anurag vohra wrote:
>
> Hi Matt,
>
> Thanks for your reply. I tried to run these simulations for 512 Ge atoms 
> with DFT section below  (no errors in output files at-least) but there are 
> some issues with value of band gap I get:
>
> According to output HOMO value is 0.14948205 a.u. (4.0676 eV), LUMO value 
> is 0.16622340 a.u. (4.5231 eV) and Fermi energy is 3.882363 eV. Now two 
> questions over here:   
>
> a) How Fermi level is below the HOMO level? It should be either at the 
> same level as HOMO as known for CP2K or in between the band gap (between 
> HOMO and LUMO)?
>
> b) Value of band gap is only 0.45 eV, whereas it is expected to 
> overestimate the band gap ~1.2eV for Hartree-Fock exchange of 0.25. I am 
> still trying to play with cut-off radius, maybe that will fix issue but is 
> there anything else which could be wrong?
>
> Both input and outputs are given below.
>
> Regards,
> Anurag  
>
> *Input:*
>
>    &AUXILIARY_DENSITY_MATRIX_METHOD
>       ADMM_PURIFICATION_METHOD NONE
>       METHOD BASIS_PROJECTION
>     &END AUXILIARY_DENSITY_MATRIX_METHOD
>     &SCF
>       ADDED_MOS 20
>       MAX_SCF 200
>       EPS_SCF 1e-06
>       SCF_GUESS RESTART
>       &DIAGONALIZATION T
>         ALGORITHM STANDARD
>       &END DIAGONALIZATION
>       &MIXING T
>         NBUFFER 4
>         BETA 1.25
>         ALPHA 0.2
>         METHOD BROYDEN_MIXING
>       &END MIXING
>       &PRINT
>         &RESTART ON
>         &END RESTART
>       &END PRINT
>       &SMEAR ON
>         METHOD FERMI_DIRAC
>         ELECTRONIC_TEMPERATURE [K] 300
>       &END SMEAR
>     &END SCF
>     &XC
>       &XC_FUNCTIONAL NO_SHORTCUT
>         &PBE .TRUE.
>           SCALE_X 0.75
>           SCALE_C 1.0
>         &END PBE
>       &END XC_FUNCTIONAL
>       &HF
>         FRACTION 0.25
>         &INTERACTION_POTENTIAL
>           T_C_G_DATA /pseudos/CP2K/t_c_g.dat
>           POTENTIAL_TYPE TRUNCATED
>           CUTOFF_RADIUS 5.0
>         &END INTERACTION_POTENTIAL
>         &SCREENING
>           EPS_SCHWARZ 1e-06
>           EPS_SCHWARZ_FORCES 1e-05
>           SCREEN_ON_INITIAL_P .TRUE.
>         &END SCREENING
>         &MEMORY
>           EPS_STORAGE_SCALING 0.1
>           MAX_MEMORY 1280
>           MAX_DISK_SPACE 2560
>         &END MEMORY
>       &END HF
>     &END XC
>     &MGRID
>       CUTOFF 250
>       NGRIDS 4
>       REL_CUTOFF 60
>     &END MGRID
>     &QS
>       EPS_PGF_ORB 1e-32
>       EPS_DEFAULT 1e-10
>       EXTRAPOLATION ASPC
>       EXTRAPOLATION_ORDER 3
>     &END QS 
>
> *Output:*
>
> *  Eigenvalues of the occupied subspace spin            
> 1 ---------------------------------------------      -0.36866786      
> -0.35966684      -0.35966682      -0.35966667      -0.35965497      
> -0.35965496      -0.35965493      -0.35085311      -0.35085308      
> -0.35085293      -0.35084203      -0.35084201      -0.35084199      
> -0.35084094      -0.35084091      -0.35084087      -0.35082991      
> -0.35082990      -0.35082981      -0.34233849      -0.34232863      
> -0.34232862      -0.34232284      -0.34231639      -0.34231470      
> -0.34231469      -0.34230397      -0.33260802      -0.33260767      
> -0.33260765      -0.33258344      -0.33258315      -0.33258297      
> -0.32446838      -0.32446831      -0.32446824      -0.32446817      
> -0.32446800      -0.32446798      -0.32445754      -0.32445749      
> -0.32445740      -0.32445732      -0.32445726      -0.32445718      
> -0.32444422      -0.32444412      -0.32444403      -0.32444393      
> -0.32444388      -0.32444376      -0.32443333      -0.32443332      
> -0.32443326      -0.32443311      -0.32443305      -0.32443299      
> -0.31715259      -0.31715254      -0.31715250      -0.31714386      
> -0.31714380      -0.31714378      -0.31714111      -0.31714099      
> -0.31714098      -0.31713109      -0.31713102      -0.31713101      
> -0.31712563      -0.31712558      -0.31712547      -0.31711948      
> -0.31711942      -0.31711941      -0.31711436      -0.31711430      
> -0.31711427      -0.31710701      -0.31710696      -0.31710688      
> -0.30070423      -0.30070420      -0.30070385      -0.30068189      
> -0.30068184      -0.30068150      -0.30067793      -0.30067792      
> -0.30067756      -0.30065361      -0.30065353      -0.30065319      
> -0.29721108      -0.29721042      -0.29721034      -0.29720261      
> -0.29720238      -0.29720224      -0.29719891      -0.29719881      
> -0.29719824      -0.29717683      -0.29717675      -0.29717662      
> -0.29717344      -0.29717340      -0.29717323      -0.29716280      
> -0.29716276      -0.29716261      -0.29715518      -0.29715492      
> -0.29715480      -0.29714478      -0.29714477      -0.29714459      
> -0.29316480      -0.29314705      -0.29314705      -0.29311726      
> -0.28754784      -0.28754735      -0.28754722      -0.28749841      
> -0.28749798      -0.28749794      -0.28116952      -0.28116939      
> -0.28116934      -0.28116899      -0.28116873      -0.28116871      
> -0.28115553      -0.28115544      -0.28115542      -0.28115514      
> -0.28115488      -0.28115488      -0.28112047      -0.28112038      
> -0.28112038      -0.28112036      -0.28112006      -0.28112002      
> -0.28110525      -0.28110524      -0.28110517      -0.28110512      
> -0.28110487      -0.28110483      -0.27781135      -0.27781133      
> -0.27780881      -0.27780103      -0.27780101      -0.27780040      
> -0.27780036      -0.27779583      -0.27779323      -0.27778528      
> -0.27776741      -0.27776740      -0.27775872      -0.27775327      
> -0.27775319      -0.27774543      -0.27773999      -0.27773992      
> -0.27773723      -0.27773716      -0.27773412      -0.27772811      
> -0.27772803      -0.27771704      -0.27394144      -0.27394142      
> -0.27394098      -0.27394098      -0.27394090      -0.27394089      
> -0.27392412      -0.27392410      -0.27392365      -0.27392364      
> -0.27392361      -0.27392354      -0.27389184      -0.27389178      
> -0.27389138      -0.27389134      -0.27389133      -0.27389122      
> -0.27387784      -0.27387781      -0.27387740      -0.27387738      
> -0.27387732      -0.27387732      -0.26421341      -0.26421329      
> -0.26421278      -0.26421276      -0.26421257      -0.26421252      
> -0.26419499      -0.26419499      -0.26419437      -0.26419428      
> -0.26419425      -0.26419402      -0.26416940      -0.26416933      
> -0.26416876      -0.26416867      -0.26416866      -0.26416838      
> -0.26415102      -0.26415097      -0.26415047      -0.26415034      
> -0.26415028      -0.26415023      -0.24317487      -0.24317478      
> -0.24317443      -0.24314999      -0.24314999      -0.24314978      
> -0.24313666      -0.24313662      -0.24313641      -0.24311188      
> -0.24311186      -0.24311167      -0.22521827      -0.22521170      
> -0.22521145      -0.22518784      -0.22518759      -0.22518116      
> -0.22330518      -0.22330517      -0.22330481      -0.22330460      
> -0.22330452      -0.22330419      -0.22329676      -0.22329674      
> -0.22329663      -0.22329623      -0.22329623      -0.22329619      
> -0.22328704      -0.22328703      -0.22328663      -0.22328650      
> -0.22328648      -0.22328611      -0.22326079      -0.22326072      
> -0.22326045      -0.22326043      -0.22326040      -0.22326023      
> -0.22127574      -0.22127572      -0.22127485      -0.22127483      
> -0.22127482      -0.22127481      -0.22125059      -0.22125058      
> -0.22124974      -0.22124967      -0.22124962      -0.22124959      
> -0.20211131      -0.20211128      -0.20211120      -0.20211070      
> -0.20211045      -0.20211036      -0.20209328      -0.20209323      
> -0.20209305      -0.20209261      -0.20209254      -0.20209251      
> -0.17749525      -0.17749523      -0.17749487      -0.17749486      
> -0.17749439      -0.17749435      -0.17749199      -0.17749198      
> -0.17749157      -0.17749154      -0.17749111      -0.17749105      
> -0.17747031      -0.17747017      -0.17746979      -0.17746979      
> -0.17746934      -0.17746933      -0.17746710      -0.17746683      
> -0.17746654      -0.17746647      -0.17746604      -0.17746595      
> -0.17663451      -0.17663447      -0.17663406      -0.17663405      
> -0.17663402      -0.17663402      -0.17661687      -0.17661687      
> -0.17661643      -0.17661643      -0.17661641      -0.17661635      
> -0.17659185      -0.17659182      -0.17659138      -0.17659136      
> -0.17659134      -0.17659131      -0.17658071      -0.17658066      
> -0.17658026      -0.17658020      -0.17658020      -0.17658018      
> -0.17498986      -0.17495580      -0.17495580      -0.17494972      
> -0.16629982      -0.16629090      -0.16629079      -0.16627983      
> -0.16627976      -0.16627618      -0.16626730      -0.16626584      
> -0.16626566      -0.16626559      -0.16626344      -0.16626339      
> -0.16624608      -0.16624605      -0.16623505      -0.16622735      
> -0.16622666      -0.16622660      -0.16622413      -0.16621929      
> -0.16621924      -0.16621413      -0.16621405      -0.16620999      
> -0.15643864      -0.15643861      -0.15643822      -0.15641993      
> -0.15641990      -0.15641952      -0.15640974      -0.15640971      
> -0.15640933      -0.15640687      -0.15640682      -0.15640644      
> -0.15639916      -0.15639905      -0.15639865      -0.15637050      
> -0.15637036      -0.15637000      -0.15636754      -0.15636742      
> -0.15636705      -0.15635491      -0.15635489      -0.15635449      
> -0.15595769      -0.15595767      -0.15595760      -0.15595741      
> -0.15595700      -0.15595698      -0.15595280      -0.15595279      
> -0.15595263      -0.15595259      -0.15595223      -0.15595212      
> -0.15592374      -0.15592371      -0.15592362      -0.15592355      
> -0.15592308      -0.15592308      -0.15591903      -0.15591899      
> -0.15591895      -0.15591880      -0.15591842      -0.15591840      
> -0.14768194      -0.14768166      -0.14768159      -0.14764491      
> -0.14764461      -0.14764457      -0.13183868      -0.13183866      
> -0.13183795      -0.13183178      -0.13183175      -0.13183103      
> -0.13181765      -0.13181762      -0.13181700      -0.13181699      
> -0.13181688      -0.13181625      -0.11570346      -0.11570339      
> -0.11570334      -0.11569256      -0.11569252      -0.11569215      
> -0.11567034      -0.11567029      -0.11567011      -0.11566072      
> -0.11566058      -0.11566053      -0.11565523      -0.11565521      
> -0.11565496      -0.11565360      -0.11565331      -0.11565325      
> -0.11563052      -0.11563046      -0.11563007      -0.11561907      
> -0.11561901      -0.11561888      -0.08482937      -0.08482932      
> -0.08482926      -0.08482894      -0.08482888      -0.08482880      
> -0.08482853      -0.08482849      -0.08482844      -0.08482825      
> -0.08482824      -0.08482814      -0.08481141      -0.08481136      
> -0.08481128      -0.08481101      -0.08481097      -0.08481082      
> -0.08481066      -0.08481060      -0.08481054      -0.08481028      
> -0.08481026      -0.08481015      -0.05825905      -0.05825889      
> -0.05825827      -0.05824506      -0.05824503      -0.05824435      
> -0.05734804      -0.05732222      -0.05730741      -0.05730739      
> -0.05728647      -0.05727187      -0.05727185      -0.05724086      
> -0.03661424      -0.03661396      -0.03661392      -0.03660754      
> -0.03660722      -0.03660722      -0.03660146      -0.03660119      
> -0.03660113      -0.03659480      -0.03659450      -0.03659446      
> -0.03480640      -0.03480639      -0.03480637      -0.03480634      
> -0.03480605      -0.03480602      -0.03480175      -0.03480173      
> -0.03480171      -0.03480167      -0.03480138      -0.03480135      
> -0.03478846      -0.03478846      -0.03478836      -0.03478831      
> -0.03478813      -0.03478801      -0.03478375      -0.03478373      
> -0.03478369      -0.03478367      -0.03478339      -0.03478335      
> -0.01877226      -0.01877225      -0.01877188      -0.01877182      
> -0.01877169      -0.01877167      -0.01876220      -0.01876218      
> -0.01876182      -0.01876174      -0.01876173      -0.01876167      
> -0.01735588      -0.01735507      -0.01735502      -0.01734532      
> -0.01734501      -0.01734451      -0.01734450      -0.01734419      
> -0.01734410      -0.01733359      -0.01733277      -0.01733274      
> -0.01255620      -0.01255593      -0.01255524      -0.01255521      
> -0.01255503      -0.01255492      -0.01253771      -0.01253738      
> -0.01253674      -0.01253669      -0.01253643      -0.01253642      
> -0.01181980      -0.01181979      -0.01181896      -0.01181732      
> -0.01181709      -0.01181709      -0.01181584      -0.01181562      
> -0.01181559      -0.01181418      -0.01181371      -0.01181371      
> -0.01181113      -0.01180909      -0.01180908      -0.01180529      
> -0.01180517      -0.01180350      -0.01178431      -0.01178424      
> -0.01178412      -0.01178406      -0.01178402      -0.01178392      
> -0.01166349      -0.01166349      -0.01166217      -0.01165912      
> -0.01165910      -0.01165828      -0.01164707      -0.01164464      
> -0.01164463      -0.01163765      -0.01162821      -0.01162820      
> -0.01162230      -0.01162194      -0.01162192      -0.01161928      
> -0.01161926      -0.01161616      -0.01161616      -0.01161553      
> -0.01161230      -0.01160817      -0.01160816      -0.01160532      
> -0.00454336      -0.00454332      -0.00454325      -0.00454321      
> -0.00454318      -0.00454315      -0.00453443      -0.00453435      
> -0.00453433      -0.00453427      -0.00453412      -0.00453409      
> -0.00453034      -0.00453027      -0.00453020      -0.00453010      
> -0.00453004      -0.00452993      -0.00452413      -0.00452411      
> -0.00452400      -0.00452394      -0.00452378      -0.00452375      
> -0.00291831      -0.00291823      -0.00291810      -0.00291802      
> -0.00291789      -0.00291783      -0.00291216      -0.00291208      
> -0.00291194      -0.00291185      -0.00291162      -0.00291160      
> -0.00289831      -0.00289830      -0.00289827      -0.00289813      
> -0.00289801      -0.00289800      -0.00289214      -0.00289200      
> -0.00289195      -0.00289194      -0.00289176      -0.00289169      
>  0.01280386       0.01280412       0.01280890       0.01281589      
>  0.01282071       0.01282093       0.02163444       0.02163445      
>  0.02163455       0.02163461       0.02163467       0.02163475      
>  0.02164362       0.02164365       0.02164376       0.02164383      
>  0.02164389       0.02164390       0.02165441       0.02165444      
>  0.02165453       0.02165458       0.02165459       0.02165463      
>  0.02167353       0.02167358       0.02167369       0.02167371      
>  0.02167376       0.02167383       0.02373159       0.02373188      
>  0.02373194       0.02375194       0.02375197       0.02375209      
>  0.02375699       0.02375701       0.02375701       0.02376154      
>  0.02376159       0.02376165       0.02400176       0.02400181      
>  0.02400218       0.02400227       0.02400283       0.02400283      
>  0.02400493       0.02400500       0.02400537       0.02400549      
>  0.02400599       0.02400604       0.02400963       0.02400967      
>  0.02401008       0.02401014       0.02401069       0.02401074      
>  0.02401285       0.02401286       0.02401329       0.02401337      
>  0.02401388       0.02401395       0.02619875       0.02619904      
>  0.02619911       0.02621151       0.02621166       0.02621171      
>  0.02621608       0.02621614       0.02621627       0.02621697      
>  0.02621715       0.02621721       0.02623235       0.02623251      
>  0.02623259       0.02624612       0.02624622       0.02624624      
>  0.02625440       0.02625455       0.02625456       0.02625564      
>  0.02625579       0.02625582       0.02877127       0.02877129      
>  0.02877158       0.02877162       0.02877174       0.02877183      
>  0.02877701       0.02877702       0.02877736       0.02877750      
>  0.02877754       0.02877775       0.02879189       0.02879189      
>  0.02879215       0.02879220       0.02879237       0.02879238      
>  0.02879750       0.02879763       0.02879792       0.02879797      
>  0.02879805       0.02879827       0.03090717       0.03090744      
>  0.03090750       0.03091791       0.03091821       0.03091827      
>  0.03092653       0.03092683       0.03092688       0.03093711      
>  0.03093738       0.03093743       0.03934270       0.03934283      
>  0.03934561       0.03934762       0.03934763       0.03935049      
>  0.04030546       0.04030897       0.04030898       0.04031880      
>  0.04031883       0.04032055       0.04032617       0.04032641      
>  0.04032643       0.04033646       0.04034462       0.04034464      
>  0.04035808       0.04035808       0.04036105       0.04036348      
>  0.04036349       0.04036433       0.04037008       0.04037011      
>  0.04037194       0.04037349       0.04037351       0.04037791      
>  0.04491163       0.04491165       0.04491167       0.04491179      
>  0.04491185       0.04491192       0.04493052       0.04493052      
>  0.04493055       0.04493064       0.04493065       0.04493077      
>  0.04495550       0.04495553       0.04495556       0.04495560      
>  0.04495566       0.04495568       0.04495946       0.04495946      
>  0.04495952       0.04495953       0.04495959       0.04495961      
>  0.05087297       0.05087301       0.05087351       0.05087715      
>  0.05087722       0.05087770       0.05090249       0.05090253      
>  0.05090305       0.05090453       0.05090459       0.05090509      
>  0.05090569       0.05090573       0.05090622       0.05091266      
>  0.05091266       0.05091318       0.05092247       0.05092250      
>  0.05092298       0.05092952       0.05092953       0.05093003      
>  0.05548238       0.05548245       0.05548358       0.05548486      
>  0.05548486       0.05548603       0.05550192       0.05550192      
>  0.05550307       0.05552016       0.05552017       0.05552135      
>  0.06660565       0.06660569       0.06660627       0.06661582      
>  0.06661586       0.06661642       0.06661723       0.06661724      
>  0.06661781       0.06662694       0.06662703       0.06662721      
>  0.06662728       0.06662758       0.06662783       0.06663142      
>  0.06663146       0.06663202       0.06665428       0.06665439      
>  0.06665494       0.06665866       0.06665869       0.06665927      
>  0.06951145       0.06951213       0.06951214       0.06951441      
>  0.06951505       0.06951507       0.06951707       0.06951774      
>  0.06951781       0.06952002       0.06952072       0.06952072      
>  0.07267135       0.07267135       0.07267139       0.07267147      
>  0.07267233       0.07267242       0.07267272       0.07267282      
>  0.07267285       0.07267287       0.07267380       0.07267382      
>  0.07268866       0.07268870       0.07268873       0.07268882      
>  0.07268971       0.07268976       0.07269013       0.07269016      
>  0.07269020       0.07269038       0.07269122       0.07269122      
>  0.07631967       0.07631968       0.07631989       0.07633033      
>  0.07633056       0.07633074       0.07633525       0.07633539      
>  0.07633576       0.07636611       0.07636613       0.07636634      
>  0.07798295       0.07798295       0.07798466       0.07798478      
>  0.07798512       0.07798512       0.07798701       0.07798702      
>  0.07798707       0.07804128       0.07804140       0.07804142      
>  0.07804497       0.07804515       0.07804516       0.07805112      
>  0.07805112       0.07805123       0.07805172       0.07805178      
>  0.07805178       0.07805902       0.07805913       0.07805915      
>  0.07976981       0.07977017       0.07977356       0.07977444      
>  0.07977458       0.07979862       0.07981609       0.07981635      
>  0.10104438       0.10106170       0.10106212       0.10107082      
>  0.10107103       0.10109063       0.10109103       0.10109855      
>  0.10112217       0.10112255       0.10113945       0.10113955      
>  0.10114391       0.10114443       0.10115709       0.10115740      
>  0.10230496       0.10230496       0.10230533       0.10232539      
>  0.10232545       0.10232586       0.10237031       0.10237041      
>  0.10237074       0.10238239       0.10238247       0.10238282      
>  0.12000840       0.12000854       0.12000860       0.12000973      
>  0.12000983       0.12000986       0.12003129       0.12003143      
>  0.12003144       0.12003249       0.12003259       0.12003259      
>  0.13479703       0.13483338       0.13483570       0.14948205 Fermi Energy 
> [eV] :    3.882363    Lowest eigenvalues of the unoccupied subspace spin    
>         1 ---------------------------------------------       0.16622340    
>    0.16622506       0.16622514*
>
> On Thursday, 25 January 2018 16:40:09 UTC+1, Matt W wrote:
>>
>> It should work. But you should carefully check that changing from 
>> purification to no purification does not much effect your results (total 
>> energies will change, but energy difference etc should be only very 
>> slightly effected).
>>
>> Matt
>>
>> On Thursday, January 25, 2018 at 3:28:30 PM UTC, anurag vohra wrote:
>>>
>>> Hi,
>>>
>>> Is there any reference available where bandgap of Ge is calculated using 
>>> PBE0 functional in CP2K?
>>>
>>> I am aware of this link:
>>>
>>>
>>> https://www.cp2k.org/_media/events:2015_user_meeting:cp2k-uk-2015-ling.pdf
>>>
>>> However, this code doesn't allows to use OT together with added MOS. 
>>> Also Purification method (*MO_DIAG*) in ADMM only works together with 
>>> OT.  
>>>
>>> *&AUXILIARY_DENSITY_MATRIX_METHOD*
>>> *METHOD BASIS_PROJECTION*
>>> *ADMM_PURIFICATION_METHOD MO_DIAG*
>>> *&END AUXILIARY_DENSITY_MATRIX_METHOD*
>>>
>>> Is it ok to run these simulations without any purification method & OT? 
>>> I am adding extra MOS over here. Standard diagonalization, broyden mixing 
>>> and smearing is used for single point energy calculation.   
>>>
>>> Regards,
>>> Anurag 
>>>
>>
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