[Wien] Magnetism of dilute alloys
Thank you for the reply! When the RMT is set to be smaller and keep the value of RMT*KMAX the same, there will be more plane waves in Wien. On the other hand, VASP is package using a plan wave basis, so I think the results of the two package will be almost the same when the RMT set to be smaller. And I did the calculations of the same system FeZn35 with spin and no spin. The result shows that the total energy of no-spin is -128273.80637250 Ry and that of spin is -128273.83372717 Ry. The former is smaller, about 0.03 Ry. On Tue, May 18, 2010 at 2:40 PM, Stefaan Cottenier Stefaan.Cottenier at ugent.be wrote: I note that the value RMT = 2.25 in my calculation FeZn35 and the value is generated automatically according the structure parameters of the system. In my opinion, the limitation of the value is zero, in my opinion, the calculation equates to VASP in this case. (I'm sorry, I don't catch the meaning of your last sentence.) My question is whether the value RMT will effect the magnetism property of a metal system? How to choose the value of RMT? The value of RMT should not affect the type of result you get (i.e. whether you find a magnetic or nonmagnetic solution). Small changes in RMT will changes to some extent the value of the spin moment reported in :MMIxxx, because the latter is the spin moment *within* the muffin tin sphere. However, this is only an apparent change. Roughly spoken, you get the same charge and spin densities, irrespective of the value of RMT. Only the portion of the total spin moment (:MMTOT) which you assign to a particular atom (:MMIxxx) is different. Stefaan ___ Wien mailing list Wien at zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien -- Bin Shao College of Information Technical Science, Nankai University 94 Weijin Rd. Nankai Dist. Tianjin 300071, China Email: binshao1118 at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20100519/8667806a/attachment.htm
[Wien] Magnetism of dilute alloys
When the RMT is set to be smaller and keep the value of RMT*KMAX the same, there will be more plane waves in Wien. On the other hand, VASP is package using a plan wave basis, so I think the results of the two package will be almost the same when the RMT set to be smaller. Good attempt, but not really true. VASP has plane waves *and* a pseudopotential. Therefore, with a reasonable number of plane waves you get a good description. If, however, you would set RMT to zero in wien, you have an all-electron calculation (no pseudopotential) with a plane wave basis. That would require zillions of basis functions -- impossible in practice. And I did the calculations of the same system FeZn35 with spin and no spin. The result shows that the total energy of no-spin is -128273.80637250 Ry and that of spin is -128273.83372717 Ry. The former is smaller, about 0.03 Ry. Fine -- this suggests that you should be able to find the magnetic solutions with VASP as well. Stefaan
[Wien] Magnetism of dilute alloys
Dear wien2k users, I am running wien version 9.2 on a machine of type cluster with operating system Centos 5.4, fortran compiler ifort and math libraries intel mkl. The purpose of my calculations in to get the magnetic property of Fe doped Zn. I generate the structure of FeZn35 by using the lattice parameter of pure Zn and making a supercell of 2x2x2, then substitutes a Zn atom with Fe atom. I use the exchange correlation of PBE-GGA and klist 11x11x11. In the process, I don't adopt any new structures provided in the Wien script *initialize calc.* and run the program by command line. After the scf calculation, it comes to that the system is magnetic with 2.54149 bohr magnetic moment. However, I did a calculation using another DFT software VASP with the same lattice parameter, the same exchange correlation, except k-mesh. In the VASP, the k-mesh is 8x8x8. But the result of VASP shows the system is nonmagnetism. Although in the calculations I did before, the results of the two software have something different within 0.1 bohr magnetic moment. The huge difference of the above result puzzled me. Any suggestion will be greatly appreciated! Thanks in advanced. Best regards, -- Bin Shao College of Information Technical Science, Nankai University 94 Weijin Rd. Nankai Dist. Tianjin 300071, China Email: binshao1118 at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20100514/ed31b011/attachment.htm
[Wien] Magnetism of dilute alloys
Probably the magnetism got lost during your vasp calculation. Is it possible to do fixed-spin-moment calculations in vasp? If so, do the vasp calculation with a fixed moment of 2.5 mu_B, and use the result of the latter calculation as starting point of a regular vasp scf-cycle. Another way to convince you about the feasibility of the magnetic result in wien2k, is to make a nonmagnetic calculation for this system by wien2k. Is the energie larger or smaller than the energy of the magnetic result? (once you have the magnetic and nonmagnetic energies with both codes, you can even compare the energy difference for the two codes). Stefaan Bin Shao wrote: Dear wien2k users, I am running wien version 9.2 on a machine of type cluster with operating system Centos 5.4, fortran compiler ifort and math libraries intel mkl. The purpose of my calculations in to get the magnetic property of Fe doped Zn. I generate the structure of FeZn35 by using the lattice parameter of pure Zn and making a supercell of 2x2x2, then substitutes a Zn atom with Fe atom. I use the exchange correlation of PBE-GGA and klist 11x11x11. In the process, I don't adopt any new structures provided in the Wien script _/initialize calc./_ and run the program by command line. After the scf calculation, it comes to that the system is magnetic with 2.54149 bohr magnetic moment. However, I did a calculation using another DFT software VASP with the same lattice parameter, the same exchange correlation, except k-mesh. In the VASP, the k-mesh is 8x8x8. But the result of VASP shows the system is nonmagnetism. Although in the calculations I did before, the results of the two software have something different within 0.1 bohr magnetic moment. The huge difference of the above result puzzled me. Any suggestion will be greatly appreciated! Thanks in advanced. Best regards, -- Bin Shao College of Information Technical Science, Nankai University 94 Weijin Rd. Nankai Dist. Tianjin 300071, China Email: binshao1118 at gmail.com mailto:binshao1118 at gmail.com ___ Wien mailing list Wien at zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
[Wien] Magnetism of dilute alloys
Thank you for the reply. I'll try it. And if the difference comes from the precision of Wien2K, e.g. the rkmax should be set larger, now rkmax = 7. On Fri, May 14, 2010 at 1:20 PM, Stefaan Cottenier Stefaan.Cottenier at ugent.be wrote: Probably the magnetism got lost during your vasp calculation. Is it possible to do fixed-spin-moment calculations in vasp? If so, do the vasp calculation with a fixed moment of 2.5 mu_B, and use the result of the latter calculation as starting point of a regular vasp scf-cycle. Another way to convince you about the feasibility of the magnetic result in wien2k, is to make a nonmagnetic calculation for this system by wien2k. Is the energie larger or smaller than the energy of the magnetic result? (once you have the magnetic and nonmagnetic energies with both codes, you can even compare the energy difference for the two codes). Stefaan Bin Shao wrote: Dear wien2k users, I am running wien version 9.2 on a machine of type cluster with operating system Centos 5.4, fortran compiler ifort and math libraries intel mkl. The purpose of my calculations in to get the magnetic property of Fe doped Zn. I generate the structure of FeZn35 by using the lattice parameter of pure Zn and making a supercell of 2x2x2, then substitutes a Zn atom with Fe atom. I use the exchange correlation of PBE-GGA and klist 11x11x11. In the process, I don't adopt any new structures provided in the Wien script _/initialize calc./_ and run the program by command line. After the scf calculation, it comes to that the system is magnetic with 2.54149 bohr magnetic moment. However, I did a calculation using another DFT software VASP with the same lattice parameter, the same exchange correlation, except k-mesh. In the VASP, the k-mesh is 8x8x8. But the result of VASP shows the system is nonmagnetism. Although in the calculations I did before, the results of the two software have something different within 0.1 bohr magnetic moment. The huge difference of the above result puzzled me. Any suggestion will be greatly appreciated! Thanks in advanced. Best regards, -- Bin Shao College of Information Technical Science, Nankai University 94 Weijin Rd. Nankai Dist. Tianjin 300071, China Email: binshao1118 at gmail.com mailto:binshao1118 at gmail.com ___ Wien mailing list Wien at zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien ___ Wien mailing list Wien at zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien -- Bin Shao College of Information Technical Science, Nankai University 94 Weijin Rd. Nankai Dist. Tianjin 300071, China Email: binshao1118 at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20100514/556fd965/attachment.htm
