[Wien] Symmetry for lapw1c in LDA+U

[D.A. Tompsett]

Dear Peter,
          thanks for the help. I am considering a system with 4f moments 
and so further reductions of symmetry to allow for the formation of 
atomic-like orbitals may be valid.

I am a bit unsure of the technical procedure to achieve this in Wien2k. If 
I would like to reduce the system symmetry further after the steps 
runsp_lapw save_lapw case initso_lapw runsp_lapw -so ie. after the 
spin-orbit part has been added and before I start ramping up the U, how 
would I go about it?

If I manually lower the symmetry group chosen in the .struct file then I 
could just add the atoms into the unit cell manually that are not produced 
by the remaining symmetry operations. Is this the logical way to approach 
this?

Alternatively should I start the entire series of calculations with the 
lower symmetry?

Thanks,
David.

On Aug 20 2008, Peter Blaha wrote:

>When adding SO AND orb; the latter is added in lapwso, which is 
>"complex" anyway.
>
>Still you have the symmetry which is compatible with a) your crystal 
>symmetry, and b) with the SO interaction (direction of magnetization).
>
>There are cases (mainly rare-earth compounds), where you may want to 
>reduce the symmetry further (to get a "localized, atomic-like state", 
>which does not obey crystal symmetry. But this requires that you 
>"understand" the symmetries and their consequences (degeneracy of states).
>
>
>D.A. Tompsett schrieb:
>> Dear All,
>>         I am using the latest WIEN2k_08.2 release on a unix platform.
>> 
>> I am attempting to calculate the eigenvalues for my system in the full
>> Brillouin zone. I wish to do so using LDA+U with S-O coupling.
>> 
>> I am running the execution commands in the following sequence as 
>> recommended so that I may ramp up the U slowly: runsp_lapw save_lapw 
>> case initso_lapw runsp_lapw -so save_lapw case runsp_lapw -so -orb
>> 
>> The question I have relates to a phrase in the UG on p.83 under the ORB 
>> function: "The presence of such an orbital field may lower the symmetry. 
>> In particular the complex version of LAPW1 must be used."
>> 
>> My question is, if the symmetry is lowered by the orbital field will 
>> the code automatically detect this and run lapw1c? In my case.dayfile 
>> this is not occuring for the -orb run:
>>     cycle 1 	(Mon Aug 18 18:15:55 BST 2008) 	(40/99 to go)
>> 
>>>   lapw0 	(18:15:55) 4.580u 0.420s 0:06.08 82.2%	0+0k 0+0io 182pf+0w
>>>   orb -up 	(18:16:01) 0.000u 0.000s 0:01.14 0.0%	0+0k 0+0io 98pf+0w
>>>   orb -dn 	(18:16:03) 0.010u 0.010s 0:00.08 25.0%	0+0k 0+0io 0pf+0w
>>>   lapw1 -up (18:16:03) 352.730u 7.760s 6:02.01 99.5% 0+0k 0+0io 302pf+0w
>>>   lapw1 -dn (18:22:05) 352.650u 7.660s 6:00.82 99.8% 0+0k 0+0io 0pf+0w
>>>   lapwso -up -orb (18:28:06) 177.240u 5.500s 3:05.50 98.5% 0+0k 0+0io 
>>> 266pf+0w
>>>   lapw2 -c -up -so (18:31:11) 115.440u 3.340s 2:01.17 98.0% 0+0k 0+0io 
>>> 239pf+0w
>>>   lapw2 -c -dn -so (18:33:13) 115.430u 3.500s 1:59.11 99.8% 0+0k 0+0io 
>>> 0pf+0w
>>>   lapwdm -up -so -c (18:35:12) 5.250u 0.620s 0:07.51 78.1% 0+0k 0+0io 
>>> 158pf+0w
>>>   lcore -up	(18:35:19) 0.050u 0.090s 0:01.60 8.7%	0+0k 0+0io 95pf+0w
>>>   lcore -dn	(18:35:21) 0.060u 0.080s 0:00.45 31.1%	0+0k 0+0io 0pf+0w
>>>   mixer 	(18:35:22) 0.360u 0.410s 0:02.45 31.4%	0+0k 0+0io 139pf+0w
>> :ENERGY convergence:  0 0.0001 0
>> :CHARGE convergence:  0 0.0000 0
>> 
>> Otherwise how do I know if I need to direct lapw1c to run and how would 
>> I do it?
>> 
>> Thank you,
>> David Tompsett
>> Quantum Matter Group
>> Cavendish Laboratory
>> J. J. Thomson Avenue
>> Cambridge CB3 0HE
>> U.K.
>> Tel: +44 7907 566351 (mobile)
>> Fax: +44 1223 337351
>> http://www-qm.phy.cam.ac.uk/
>> 
>> 
>> 
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>

-- 
David A. Tompsett
Quantum Matter Group
Cavendish Laboratory
J. J. Thomson Avenue
Cambridge CB3 0HE
U.K.
Tel: +44 7907 566351 (mobile)
Fax: +44 1223 337351
http://www-qm.phy.cam.ac.uk/