Dear Martin Pieper, Thank you for your reply.
Actually, the energy difference can be observed by the photoluminescence experiment. I want to make a demonstration for the experiment from first-principles calculation. May I just ask why you go for the energy and not for the magnetization or > the susceptibility? I don't know how to calculate the susceptibility of a material from first-principles calculation. According to the definition, it is a constant indicates the response of a material to an external magnetic field. I have got the magnetic moments for a give field, then how to get the susceptibility? Besides, I think the magnetic moments are almost the same as 4T when I changed the magnitude of the magnetic field. If there is some change of the crystal field ground state this should > show. Do you mean that the magnetic filed may be change the crystal field? I am not quite sure how to connect these two things, the magnetic field and crystal field. Best, Bin On Fri, Aug 7, 2015 at 6:35 AM, pieper <pie...@ifp.tuwien.ac.at> wrote: > Dear Bin Shao, > > unfortunately I am travelling and won't be able to contribute during the > next days. I am looking forward to comments from people with experience in > calculations with rare earths. > > May I just ask why you go for the energy and not for the magnetization or > the susceptibility? If there is some change of the crystal field ground > state this should show. From your calculation you get the size of the > magnetic moments for a given field, from that you get a susceptibility. > From what you say something happens around 4 T. I cannot guess from the > information I have what, but I would expect it to show in the > susceptibility as well. > > Good luck with this interesting problem > > Martin Pieper > > > --- > Dr. Martin Pieper > Karl-Franzens University > Institute of Physics > Universitätsplatz 5 > A-8010 Graz > Austria > Tel.: +43-(0)316-380-8564 > > > Am 06.08.2015 15:47, schrieb Bin Shao: > >> Dear Martin Pieper, >> >> Thank you for your comments! >> >> Actually, I intend to demonstrate that the energy difference between >> the ground state of Er^3+ (S=3/2; L=6; J=15/2) and the excited state >> (S=3/2; L=0; J=3/2) can be tuned by the external magnetic field, With >> the magnetic filed and the crystal field, the excited state splits >> into four states, |+3/2>, |+1/2>, |-1/2>, and |-3/2>. For the 45 Tesla >> magnetic field, the delta energy between the |+3/2> and |-3/2> is over >> 10 meV. Since we can not directly get the excited state in wien2k, >> even by forcing the occupation number, the calculation will still be >> trick. >> >> However, because the spin quantum number of the two states is the same >> (S=3/2), there is no spin flip from the ground state to the excited >> state. In this case, we can estimate the energy difference between the >> ground state and the excited state by calculating the energy >> difference between the occupied states of f electron in minority spin >> of the ground state and the unoccupied counterparts in minority spin >> of the ground state. The energy difference should become smaller with >> increasing the magnetic field, which can be attributed to the lower in >> energy of the |-3/2> state relative to the |+/-3/2> state with no >> magnetic field. >> >> Since the energy shift is in the magnitude of meV, we can not seen >> this shift from the dos calculation due to the smear of the dos. Since >> the f band is usually very local and the band is very flat, so I >> checked the eigenvalues of the 7 f-electron at the Gamma point and try >> to show the energy shift from the variations of the eigenvalues. >> However, the results show that there is only an energy shift from the >> 0 T to 4 T. When the magnetic filed is increasing, the eigenvalues are >> almost the same as that of 4 T. >> >> This most probably is the old problem of the energy zero in >>> disguise. >>> >> >> This may be the problem. But I have calculated all the energy >> differences between the 3 unoccupied and 4 occupied states of f >> electron in minority spin, the 12 (3*4) values are keep the same trend >> while the magnetic filed is varied and they are all flat. For the >> different f states, they get different J and the energy shifts >> (g_J*mu_B*J*B) induced by the magnetic filed should be also different. >> So I am confused. It should be noted that the energy difference is >> independent to the energy zero. >> >> Best, >> >> Bin >> >> On Thu, Aug 6, 2015 at 7:23 PM, pieper <pie...@ifp.tuwien.ac.at> >> wrote: >> >> As an afterthought: >>> >>> This most probably is the old problem of the energy zero in >>> disguise. The Zeeman interaction you estimated and as accounted for >>> in Wien2k is basically g*mu_B*S*B. It gives you the energy >>> difference between a moment pointing up and one pointing down. >>> However, it has a vanishing trace, the zero is at B=0 and the center >>> stays there. >>> >>> Best regards, >>> >>> Martin Pieper >>> >>> --- >>> Dr. Martin Pieper >>> Karl-Franzens University >>> Institute of Physics >>> Universitätsplatz 5 >>> A-8010 Graz >>> Austria >>> Tel.: +43-(0)316-380-8564 [3] >>> >>> Am 06.08.2015 04:55, schrieb Bin Shao: >>> >>> Dear all, >>>> >>>> I made calculations of a compound with Er^3+(4f^11 5d^0 6s^0, >>>> ground >>>> state S=3/2, L=6, J=15/2) doping under an external magnetic >>>> field. I >>>> got the corresponding occupation of Er^3+ with 7 electrons in >>>> majority >>>> spin and 4 electrons in minority spin. With soc including, I got >>>> eigenvalues at Gamma point of the Er^3+ under the magnetic field >>>> from >>>> 4 Tesla to 45 Tesla. However, the picture indicates that the >>>> eigenvalues with the different magnetic fields almost keep the >>>> same as >>>> that of 4 T. Why? According to a simple estimation, the magnetic >>>> field >>>> of 45 T will introduce an energy shift about 10 meV, that would >>>> definitely be seen from the figure. >>>> >>>> Any comments will be appreciated. Thank you in advance! >>>> >>>> Best regards, >>>> >>>> Bin >>>> >>>> _______________________________________________ >>>> Wien mailing list >>>> Wien@zeus.theochem.tuwien.ac.at >>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien [1] >>>> SEARCH the MAILING-LIST at: >>>> >>>> >>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >> >>> [2] >>>> >>> >>> _______________________________________________ >>> Wien mailing list >>> Wien@zeus.theochem.tuwien.ac.at >>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien [1] >>> SEARCH the MAILING-LIST at: >>> >>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >> >>> [2] >>> >> >> -- >> >> Bin Shao >> Postdoc >> Department of Physics, Tsinghua University >> Beijing 100084, P. R. China >> Email: binshao1...@gmail.com >> >> Links: >> ------ >> [1] http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> [2] >> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >> [3] tel:%2B43-%280%29316-380-8564 >> >> _______________________________________________ >> 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 > -- Bin Shao Postdoc Department of Physics, Tsinghua University Beijing 100084, P. R. China Email: binshao1...@gmail.com
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