Hi all, I am not calculating MR directly from WIEN2K, what I want to do is to get a band structure at particular direction of magnetic field (say 3T at different angle 20, 40, 60, 80 and so on...) with current. I shall use that band structure in DMFT to get resistance. So I asked how to apply magnetic field and electric field in WIEN2K at different direction at a time. With inorb input we can apply magnetic field at certain direction but how to apply electric field at the same time.
I am not using boltztrap. On Wed, May 23, 2018 at 10:57 AM, Karel Vyborny <vybor...@fzu.cz> wrote: > Hi Gavin, > let me add to what you write and also correct one thing you mention. > First, you are right that WIEN2k is not very useful for calculating MR. > Magnetoresistances make a large (and diverse) field, so one should be more > specific about what exactly is to be calculated. But if I consider > anisotropic magnetoresistance (AMR), for example, you need band structure > and a model for scattering to get a theoretical prediction. The former can > be obtained by WIEN2k but not the latter (at least not in a straightforward > manner). In boltztrap, they get away with "constant Gamma" (one > phenomenological relaxation time) for example and this, most likely, misses > the relevant physics of AMR. > Regarding magnetic field, I'd call ~30 T the state-of-the art: for you, > the nearest option would be Florida (NHMFL), similar European facilities > are in France (Grenoble) and the Netherlands. > > Anyway, Sudipta may want to be a little more specific about the object of > study so as to get more of advice... > > Cheers, > > Karel > > > > PS: a bit self-advertising... Look at PRB 80, 165204 or > > https://arxiv.org/abs/0906.3151 > > Fig. 1 is a graphical summary of how AMR may arise. > > --- x --- > dr. Karel Vyborny > Fyzikalni ustav AV CR, v.v.i. > Cukrovarnicka 10 > Praha 6, CZ-16253 > tel: +420220318459 > > > On Tue, 22 May 2018, Gavin Abo wrote: > > >> Someone else may know differently, but as far as I know, WIEN2k has no >> function for calculating MR (magnetoresistance). >> >> I don't know the details of what your are trying to do exactly, but it may >> be that WIEN2k's magnetic field doesn't do what you think it does. >> >> Refer to the previous posts: >> >> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at >> /msg16108.html >> >> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at >> /msg11093.html >> >> For example a VSM with Magneto Resistance option can only apply up to 3.5 >> T >> [ http://www.microsense.net/products-vsm.htm ]. Some of the best >> electromagnets in the world cannot apply too much higher magnetic fields >> than that. In the above post, at least a 10 T magnetic field has to be >> applied to even see an effect. However, I don't know how to properly >> explain that. My guess is that might be because WIEN2k's magnetic field >> is >> an atomic local field instead of a micro/macro uniform field. >> >> Do you maybe need a spin-polarized current in a spin-torque based >> micromagnetic simulator like oommf [ https://math.nist.gov/oommf/ , >> http://layer.uci.agh.edu.pl/M.Frankowski/download.html ], LLG >> Micromagnetic >> Simulator [http://llgmicro.home.mindspring.com/DataRep/HysAndMRLoops/ >> HysAndMrFrame.htm >> ], or VAMPIRE [ http://vampire.york.ac.uk/research/ ]? >> >> Or are you trying to calculate magnetic anisotropy energy (MAE) [ >> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at >> /msg09408.html >> ]? >> >> I never figured out how to do it, but tunneling current is a function of >> density of states, fermi functions, and tunneling probability [ >> http://dx.doi.org/10.9756/BIJPSIC.3129 ]. So I thought there might be a >> slight possibility to extract data from WIEN2k and post calculate that. >> >> Hope that can help and good luck. >> >> On 5/22/2018 9:21 AM, sudipta wrote: >> I want to calculate anisotropy in magnetoresistance. I want to >> to apply both magnetic field and current at same time to a >> system. In wien2k through inorb >> I can apply magnetic field, but how to give current at the same time. >> >> -- >> Sudipta koley >> Department of Physics >> IIT KHARAGPUR >> >> >> >> -- Sudipta koley Department of Physics IIT KHARAGPUR
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