[Pw_forum] GWW-band

Thu Sep 3 17:55:00 CEST 2009

hi.
a very small comment:

1) keep in mind that for this kind of materials if you want to perform a
nice GW calculation is bettter to use pseudopotential with semicore states
inside.
2) are yiou sure to be converged with the kpoint ?
3) and in particular with the nunmber of G vectors?

i think also the others with hands-on-gw in pwscf can tell you more about.

ciao.
federico iori.

Dr. Federico Iori, PhD!

Laboratoire des Solides Irradiés,
Ecole Polytechnique - CEA/DSM, CNRS
91128 Palaiseau, France

www.etsf.polytechnique.fr

phone: +33 (0) 1 69 33 44 85
emails: federico.iori @ polytechnique.edu
       iori.federico @ unimore.it
http://www.pdmodena.it/
http://www.comune.mo.it

> Hi all
>
>
> I am trying to use implemented approach GWW in espresso to obtain
> quasiparticle state for bulk TiO2 ,but I didn,t succeed to get true band
> gap by GW density of state.
> I used 10 10 12 kmesh for k sampling but I don't know which file and which
> rows contains dielectric constant. when I grep E_HEAD ,the last lines is
> E_HEAD : 58 (-0.288322417972075195E-19,-0.347622164532722579E-06)
>  E_HEAD : 59 (0.136048521030191330E-19,-0.268035068560476896E-06)
>  E_HEAD : 60 (-0.562749703002366818E-20,-0.199037475630983443E-06)
>  E_HEAD : 61 (-0.246456835447587453E-19,-0.139320684851361126E-06)
>  E_HEAD : 62 (-0.140385361912330342E-20,-0.874710056217020343E-07)
>  E_HEAD : 63 (-0.136889611087276274E-19,-0.425462567302966249E-07)
>  E_HEAD : 64 (0.768141330640736074E-21,-0.345502880250938209E-08)
>  E_HEAD : 65 (0.107544342599385735E-20,0.304924298030858145E-07)
>  E_HEAD : 66 (-0.671894800358640115E-21,0.599998026878208404E-07)
>  E_HEAD : 67 (-0.375064376440559633E-20,0.856803318704701437E-07)
>  E_HEAD : 68 (0.129039143800604427E-20,0.107981120709046864E-06)
>  E_HEAD : 69 (-0.152241559615558039E-19,0.127297350596598846E-06)
>  E_HEAD : 70 (-0.244342562407378874E-20,0.144032713772979207E-06)
>  E_HEAD : 71 (0.198849485733610600E-19,0.158423408825083901E-06)
>  E_HEAD : 72 (0.219404232386768220E-20,0.170765538857496266E-06)
>  E_HEAD : 73 (0.813380241001557854E-20,0.181265846697849958E-06)
>  E_HEAD : 74 (-0.509064059105312810E-20,0.190124058103262224E-06)
>  E_HEAD : 75 (-0.107771697951803568E-19,0.197507480698692005E-06)
>  E_HEAD : 76 (-0.755628381457475164E-20,0.203488676149189520E-06)
>  E_HEAD : 77 (0.371877756929380836E-21,0.208211859121554605E-06)
>  E_HEAD : 78 (-0.250163334688176281E-19,0.211741944281895265E-06)
>  E_HEAD : 79 (-0.450176577358151232E-20,0.214163773837653336E-06)
>  E_HEAD : 80 (0.111342594432056654E-20,0.215490995789092124E-06)
>
>
> what is these two columns? where do I look for dielectric constant?
> also when I grep the energy in exchange file I see
> X energy 1 -3.13056306094735648
>  X energy 2 -3.13125888267243768
>  X energy 3 -2.56505488760584210
>  X energy 4 -2.56505496437444780
>  X energy 5 -2.56683481217169884
>  X energy 6 -2.56683439322773843
>  X energy 7 -2.57403536452406989
>  X energy 8 -2.57295775811234151
>  X energy 9 -2.29952361470927169
>  X energy 10 -2.36757500687829703
>  X energy 11 -2.37632661585543126
>  X energy 12 -2.37632650375416299
>  X energy 13 -1.72370046221945539
>  X energy 14 -1.77636454255141807
>  X energy 15 -1.60170507625502379
>  X energy 16 -1.81076344235177400
>  X energy 17 -1.81076344671808909
>  X energy 18 -1.76589211249002198
>  X energy 19 -1.76589206392332332
>  X energy 20 -1.82208492695257473
>  X energy 21 -1.85042251355195186
>  X energy 22 -1.82815140295191192
>  X energy 23 -1.82815105271344058
>  X energy 24 -1.82718632043692120
>  X energy 25 -0.890395593964818821
>  X energy 26 -0.887974129642995047
>  X energy 27 -0.900839858974197383
>  X energy 28 -0.902277881230984180
>  X energy 29 -0.902276970932468392
>  X energy 30 -1.04934158998102989
>  X energy 31 -0.962865050316516147
>  X energy 32 -1.11061163384487793
>  X energy 33 -1.11061206732082796
>  X energy 34 -1.06420854530274700
>  X energy 35 -0.523436808399921905
>  X energy 36 -0.406604087930116875
>  X energy 37 -0.406604162637408506
>  X energy 38 -0.453038499132750461
>  X energy 39 -0.368261805733013314
>  X energy 40 -0.350145281021921162
>  X energy 41 -0.575993591072415878
>  X energy 42 -0.419593201827778928
>  X energy 43 -0.419593052276878598
>  X energy 44 -0.234200550211784625
>  X energy 45 -0.391296377238919968
>  X energy 46 -0.320118869687510410
>  X energy 47 -0.274223229681573089
>  X energy 48 -0.274223174645249645
>  X energy 49 -0.203773634312640867
>  X energy 50 -0.201021532629956590
> and it seems to be converged.
>
>
>
> so what is the problem that I get very wide gap(about 10 eV)?
> I attach  my script for this material. Please say how can I do that?
> thanks a lot
>
>
> Ali Kazempour
>
> Physics department, Isfahan University of Technology
>
> 84156 Isfahan, Iran.            Tel-1:  +98 311 391 3733
>
> Fax: +98 311 391 2376      Tel-2:  +98 311 391 2375
>
>
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