Re: [Wien] AFM calculations for YBCO6
This is a problem I had studied before, but non magnetic, so I was curious to try the magnetic case; w With YBa2Cu3O7 you have magnetism and superconductivty! braking one of Matthias rules The result I got for, YBa2Cu3O6, was that Cu1 MM=0.0007 or "non magnetic" as far as the calculations show. Cu2=0.5873 with U=4eV So, you have to study only Cu2 for magnetism. From my point of view you the most and I would guess only ordering of the inplane spins is like a chess board, alternating un and dn. the interplanar Cu2-Cu2 ordering can be up-up or up-dn, but since there are no oxygen atoms between the planes the difference should be quite small. I did the calculation with RxK=7 and 100 k-points with 4 parallel cores, it took half an hour. In the supercell output you have to delete all the numbers Ba 1 => Ba, O 1 => O and only number 1 and 2 the Cu as you want to order them I did; Cu 00x and 1/2,1/2,x as Cu 1 and later as 'up' and for 0,1/2,x and 1/2,0,x as Cu 2 and later as 'dn' Now you can have 00,-x as 'dn' and 0,1/2,-x as up and this gives another ordering De: wien-boun...@zeus.theochem.tuwien.ac.at en nombre de Madesis Ioannis(John) Enviado: sábado, 16 de mayo de 2015 01:09 p. m. Para: Wien Asunto: Re: [Wien] AFM calculations for YBCO6 Mr. Delamora, first of all thank you for your dedication, and thorough examination of my problem. I haven't fully tested your solution, however, there are plenty of AFM orderings that I wish to test such as A, G and C type, all of which are different combinations of in-plane antiferromagnetism. From first trials of your solution, what troubles me is the fact that the case_super.struct file does not include any numbers such as Cu1, O3. However, I have noticed that some of the atoms have "MULT= 2" or "MULT= 4" and present additional 1 or 3 positions. So I thought of the following: Keep the 1 x 1 x 1 cell, for the sake of calculations, and split by myself the Cu1 atoms from 1 atom of MULT= 4, to 2 groups of MULT= 2, and use your solution of naming appropriately each atom. I know that you suggested something particular, and thank you, but I need to keep the computational cost low. Last, I change the space group to "1". After I do what I said, I run an initialization, and a proper space group is defined. How is that for a solution? -- Ioannis Madesis (Μαδέσης Ιωάννης) PhD Student Atomic and Molecular Physics Department of Physics University of Crete (0030)-210-6503598 ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] AFM calculations for YBCO6
Mr. Delamora, first of all thank you for your dedication, and thorough examination of my problem. I haven't fully tested your solution, however, there are plenty of AFM orderings that I wish to test such as A, G and C type, all of which are different combinations of in-plane antiferromagnetism. From first trials of your solution, what troubles me is the fact that the case_super.struct file does not include any numbers such as Cu1, O3. However, I have noticed that some of the atoms have "MULT= 2" or "MULT= 4" and present additional 1 or 3 positions. So I thought of the following: Keep the 1 x 1 x 1 cell, for the sake of calculations, and split by myself the Cu1 atoms from 1 atom of MULT= 4, to 2 groups of MULT= 2, and use your solution of naming appropriately each atom. I know that you suggested something particular, and thank you, but I need to keep the computational cost low. Last, I change the space group to "1". After I do what I said, I run an initialization, and a proper space group is defined. How is that for a solution? -- Ioannis Madesis (Μαδέσης Ιωάννης) PhD Student Atomic and Molecular Physics Department of Physics University of Crete (0030)-210-6503598 ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Adding excitonic effects
FYI, there is a separate BSE code for WIEN2k called BSE@WIEN2k. It seems to require a cluster with hundreds of cores and a large amount of memory as described on slide 23 in the document at: http://www.wien2k.at/reg_user/textbooks/WIEN2k_lecture-notes_2013/DFT_advanced.pdf It cannot be downloadable from Dr. C. Ambrosch-Draxl's old website anymore as it no longer exists. However, you should be able to still read about it on wayback: https://web.archive.org/web/20120415092421/http://amadm.unileoben.ac.at/codes_wien2k.html If your interested in it, I think you can try requesting it from Dr. R. Laskowski: http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg03642.html On 5/16/2015 12:28 AM, Xavier Rocquefelte wrote: To properly describe an exciton, which is a two-particle entitie, you need a two-particle theory at least. DFT is a one particle theory, thus it is not suited to properly describe excitonic effects. For solids you must use the Bethe Salpeter Equation (BSE) which is implemented in other codes and very expensive in terms of computational time and memory. Another strategy is to mimick the effect of the exciton on the optical properties using DFT and a corehole approach. This last strategy is pragmatic and not exact, but it allows to deals with this 2-particle problem using a one-particle approach in a mean-field manner. Usually, a half corehole is used. It corresponds to the Slater transition state and it gives nice results in general. What kind of transtions are your doing? Does it implies core states? If yes you can easily remove half an electron in the file case.inc. If the transition is from valence states, the problem is more tricky to solve. Best Regards Xavier Dileep Krishnan a écrit : > Hi Users and Developers, > > I was calculating optical properties by OPTIC program. How can I add > excitonic effects into the calculation? > > -- > Dileep Krishnan, > Int. Ph. D Student, > International Centre for Materials Science (ICMS), > Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), > Jakkur, Bangalore-560064, > INDIA. ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Adding excitonic effects
Here is a document that can be usefull in which Peter discussed briefly "valence hole" for emission spectra: http://www.wien2k.at/reg_user/textbooks/WIEN2k_lecture-notes_2011/Blaha_xas_eels.pdf Regards Xavier Dileep Krishnan a écrit : > Dear Xavier, > > Thank you very much for your quick and detailed reply. I am > calculating the valance optical properties, where the hole is > positioned in the valance states; JDOS, Energy loss function etc. > > Thanks > > - Original Message - > From: "Xavier Rocquefelte" > To: "A Mailing list for WIEN2k users" > Sent: Saturday, May 16, 2015 11:58:08 AM > Subject: Re: [Wien] Adding excitonic effects > > > To properly describe an exciton, which is a two-particle entitie, you > need a two-particle theory at least. > DFT is a one particle theory, thus it is not suited to properly > describe excitonic effects. > For solids you must use the Bethe Salpeter Equation (BSE) which is > implemented in other codes and very expensive in terms of > computational time and memory. Another strategy is to mimick the > effect of the exciton on the optical properties using DFT and a > corehole approach. This last strategy is pragmatic and not exact, but > it allows to deals with this 2-particle problem using a one-particle > approach in a mean-field manner. Usually, a half corehole is used. It > corresponds to the Slater transition state and it gives nice results > in general. What kind of transtions are your doing? Does it implies > core states? If yes you can easily remove half an electron in the > file case.inc. If the transition is from valence states, the problem > is more tricky to solve. > Best Regards > Xavier > > > Dileep Krishnan a écrit : > >> Hi Users and Developers, >> >> I was calculating optical properties by OPTIC program. How can I add >> excitonic effects into the calculation? >> >> -- >> Dileep Krishnan, >> Int. Ph. D Student, >> International Centre for Materials Science (ICMS), >> Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), >> Jakkur, Bangalore-560064, >> INDIA. >> ___ >> Wien mailing list >> Wien@zeus.theochem.tuwien.ac.at >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> SEARCH the MAILING-LIST at: >> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >> > > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > > -- > Dileep Krishnan, > Int. Ph. D Student, > International Centre for Materials Science (ICMS), > Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), > Jakkur, Bangalore-560064, > INDIA. > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Adding excitonic effects
Dear Xavier, Thank you very much for your quick and detailed reply. I am calculating the valance optical properties, where the hole is positioned in the valance states; JDOS, Energy loss function etc. Thanks - Original Message - From: "Xavier Rocquefelte" To: "A Mailing list for WIEN2k users" Sent: Saturday, May 16, 2015 11:58:08 AM Subject: Re: [Wien] Adding excitonic effects To properly describe an exciton, which is a two-particle entitie, you need a two-particle theory at least. DFT is a one particle theory, thus it is not suited to properly describe excitonic effects. For solids you must use the Bethe Salpeter Equation (BSE) which is implemented in other codes and very expensive in terms of computational time and memory. Another strategy is to mimick the effect of the exciton on the optical properties using DFT and a corehole approach. This last strategy is pragmatic and not exact, but it allows to deals with this 2-particle problem using a one-particle approach in a mean-field manner. Usually, a half corehole is used. It corresponds to the Slater transition state and it gives nice results in general. What kind of transtions are your doing? Does it implies core states? If yes you can easily remove half an electron in the file case.inc. If the transition is from valence states, the problem is more tricky to solve. Best Regards Xavier Dileep Krishnan a écrit : > Hi Users and Developers, > > I was calculating optical properties by OPTIC program. How can I add > excitonic effects into the calculation? > > -- > Dileep Krishnan, > Int. Ph. D Student, > International Centre for Materials Science (ICMS), > Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), > Jakkur, Bangalore-560064, > INDIA. > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html -- Dileep Krishnan, Int. Ph. D Student, International Centre for Materials Science (ICMS), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-560064, INDIA. ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
