[Pw_forum] Total magnetization and local magnetic moment
Padmaja Patnaik
padmaja_patnaik at yahoo.co.uk
Tue Jul 6 11:34:14 CEST 2010
First of all thanks a lot for your suggestions.
As you mentioned that the super cell atomic positions are not correct then why the code is not giving error?
Coming to the magnetic moment querry, as you said the d electrons get filled and thus loosing the magnetic moment. But then one can expect that the moment may be trasffered to some other atom in the cell. But this also in not true in my result. Can this error be because i am doing the scf calculations for gamma point only and then the DOS calculations for 2*2*2 k points mesh? This is the only thing coming to my mind where i can be wrong. Is the difference in k point mesh give such a big difference in the magnetization value, total magnetization is > 1 and local moment is zero?
Please suggest.
Regards
Padmaja Patnaik
Research Scholar
Dept of Physics
IIT Bombay
Mumbai, India
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------------------------------
Message: 3
Date: Mon, 05 Jul 2010 12:43:52 +0200
From: Gabriele Sclauzero <sclauzer at sissa.it>
Subject: Re: [Pw_forum] Total magnetization and local magnetic moment
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID: <4C31B768.80500 at sissa.it>
Content-Type: text/plain; charset="iso-8859-1"
On 07/05/2010 12:05 PM, Padmaja Patnaik wrote:
> I have proceeded with the supercell which is giving correct DOS. Here
> is the value of total magnetizatin from the scf.out file without
> relaxation.
>
> ! total energy = -1494.09037638 Ry
> Harris-Foulkes estimate = -1494.09037639 Ry
> estimated scf accuracy < 6.7E-09 Ry
>
> The total energy is the sum of the following terms:
>
> one-electron contribution = 257.19918198 Ry
> hartree contribution = 202.08158140 Ry
> xc contribution = -548.49776710 Ry
> ewald contribution = -1404.85946098 Ry
> smearing contrib. (-TS) = -0.01391169 Ry
>
> total magnetization = 1.02 Bohr mag/cell
> absolute magnetization = 1.12 Bohr mag/cell
>
> convergence has been achieved in 17 iterations
> ------------------------------------------------------------------------
> Here is the portion of the file *.pdos.out without relaxation
>
> Atom # 1: total charge = 14.3653, s = 2.4622, p = 6.8403, d =
> 5.0628,
> spin up = 7.7466, s = 1.2349, p = 3.4229, d
> = 3.0889,
> spin down = 6.6187, s = 1.2274, p = 3.4174, d
> = 1.9739,
> polarization = 1.1279, s = 0.0075, p = 0.0054, d
> = 1.1150,
> Atom # 2: total charge = 2.9244, s = 0.8587, p = 2.0656, d
> = 0.0000,
> spin up = 1.4798, s = 0.4351, p = 1.0446, d
> = 0.0000,
> spin down = 1.4446, s = 0.4236, p = 1.0210, d
> = 0.0000,
> polarization = 0.0352, s = 0.0115, p = 0.0236, d
> = 0.0000,
> Atom # 3: total charge = 2.9244, s = 0.8587, p = 2.0656, d
> = 0.0000,
> spin up = 1.4798, s = 0.4351, p = 1.0446, d
> = 0.0000,
> spin down = 1.4446, s = 0.4236, p = 1.0210, d
> = 0.0000,
> polarization = 0.0352, s = 0.0115, p = 0.0236, d
> = 0.0000,
> -----------------------------------------------------------------------------------------------------------------
> As you can see atom number 1(this is the impurity) is showing a local
> magnetic moment. Now, below i add portions of the same two files from
> with relaxation calculations.
> ! total energy = -1494.15610974 Ry
> Harris-Foulkes estimate = -1494.15610974 Ry
> estimated scf accuracy < 1.9E-10 Ry
>
> The total energy is the sum of the following terms:
>
> one-electron contribution = 270.52901167 Ry
> hartree contribution = 195.52169853 Ry
> xc contribution = -548.43270406 Ry
> ewald contribution = -1411.76028316 Ry
> smearing contrib. (-TS) = -0.01383273 Ry
>
> total magnetization = 1.13 Bohr mag/cell
> absolute magnetization = 1.26 Bohr mag/cell
>
> convergence has been achieved in 9 iterations
>
>
It looks like your impurity (Ge, I guess) acquires a lot of charge upon
relaxing the structure, so that the d electrons get filled and you lose
the local moment. This may be a real description or some spurious effect
due to orbitals overlap (though it's unlikely if these are very
localized 3d electrons).
About the total magnetization, well I don't know. It may come from
neighboring atoms if they have donated some charge to the impurity.
HTH
GS
> ------------------------------------------------------------------------------------------------------------
> Atom # 1: total charge = 19.3947, s = 2.5253, p = 7.6414, d =
> 9.2280,
> spin up = 9.7222, s = 1.2688, p = 3.8289, d
> = 4.6245,
> spin down = 9.6725, s = 1.2566, p = 3.8125, d
> = 4.6035,
> polarization = 0.0496, s = 0.0122, p = 0.0164, d
> = 0.0210,
> Atom # 2: total charge = 3.0599, s = 0.9045, p = 2.1555, d
> = 0.0000,
> spin up = 1.5315, s = 0.4527, p = 1.0787, d
> = 0.0000,
> spin down = 1.5285, s = 0.4517, p = 1.0767, d
> = 0.0000,
> polarization = 0.0030, s = 0.0010, p = 0.0020, d
> = 0.0000,
> Atom # 3: total charge = 3.0599, s = 0.9045, p = 2.1555, d
> = 0.0000,
> spin up = 1.5315, s = 0.4527, p = 1.0787, d
> = 0.0000,
> spin down = 1.5285, s = 0.4517, p = 1.0767, d
> = 0.0000,
> polarization = 0.0030, s = 0.0010, p = 0.0020, d
> = 0.0000,
> ----------------------------------------------------------------------------------------------------------------------
> Here as you can see the total magnetization increases but the atom
> number 1 (impurity) is showing zero local magnetic moment.
> I hope i made the problem more clear this time.
>
> Regards
>
--
Gabriele Sclauzero, EPFL SB ITP CSEA
PH H2 462, Station 3, CH-1015 Lausanne
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