- 1
- Independent international Scientific Consultant, email: mcphase@icloud.com
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- 2
- Dept. Physics and Astronomy, Seoul National University, Seoul 151-742, Korea
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- 3
- Universität Regensburg
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- 4
- University of Oxford, Physics Department, Clarendon Laboratory, Parks Road, Oxford, UK
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- 5
- Forschungszentrum Jülich, D-52425 Jülich, Germany
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- 6
- Wien, Austria
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- 7
- The Hamiltonian of the standard model of rare earth magnetism
is described in section 5.
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- 8
- Note that these conditions are essential and put a limit to the
applicability of the theory, for example in the case of charge transfer excitations from
one subsystem to the next.
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- 9
- For further information on the notation and symmetry restrictions to the
parameters in the Hamiltonian refer to [1].
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- 10
- The procedure is described in detail in [20].
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- 11
- see section 19
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- 12
- ...within the
ground state multiplet of the 4f electron wave function.
The first term in equ. 25 describes the crystal field, the second the
effect of a magnetic field (Zeeman term). The strength of the crystal field is given by the
crystal field parameters
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- 13
- point charges on the
neighbouring atoms, for details on these calculations see [27]
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- 14
- see section 19)
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- 15
- In addition to
the module also returns
the partition sum
and the magnetic energy
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- 16
- Note that if you use the
module cfield, the choice is more unconventional:
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and
Tools for rotating crystal field parameters are described in appendix I.
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- 17
- section 17
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- 18
-
To trigger the Monte Carlo calculation set NOFMCSTEPS to a nonzero value. Then
after MAXNOFMFLOOPS has been reached the program switches into Monte Carlo walk mode with randomly
choosing energy eigenstates and computing total energy of a supercell
(NOFMCSTEPS times per spin in the supercell).
The initial quantum state is chosen such as to match most closely the meanfield state/ initial
configuration. The single ion program is called with
and delivers a random energy eigenstate
and the energy of the Hamiltonian is updated according to the Metropolis algorithm [2].
The final state is saved in mcphas.sps and averaged energy, magnetic moment are calculated and stored
in mcphas.fum.
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- 19
- for electric fields
will contain also the electric field, compare
section 11
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- 20
- Note two
special cases:If MAXNOFMFLOOPS=1, then the mean fields are calculated from the initial values
of the spin configuration and free energy is evaluated immediately without checking convergence.
If MAXNOFMFLOOPS=2, then from calculated mean fields the spins are calculated and
free energy is evaluated, without checking convergence. For MAXNOFMFLOOPS
2 free energy is
only evaluated if the iteration reached the convergence limit specified by MAXSTAMF.
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- 21
- Alternatively, one may make use of the program spins.
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- 22
-
,
if
is not parallel to the rotation axis. Thus for some rotation the elastic energy
will depend on rotation angle if transversal springs are introduced.
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- 23
- S. Bluegel, Juelich, private communication
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- 24
- Note that we do not calculate all the
terms in the braces in the first line of equation 4. In particular using the
central field approximation the first summation produces Hydrogen-like energy levels, called
configurations, which are split into terms by the second summation. What we refer to
as the Coulomb interaction is only this second summation, and we shall consider the lowest
energy configuration only. This configuration corresponds to the outer most electrons in ion, and is
labelled
, for example,
for Ce
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- 25
- For the case of
-coupling this corresponds to ignoring the Coulomb and SO
interactions, which are in this limit both much larger than the CF. For
-coupling, the Coulomb
interaction is treated as small and neglected, but the spin-orbit interaction is considered.
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- 26
- Also
denoted
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- 27
- Equation 11
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- 28
- Except for the case of the rotation group in 3 dimensions, SO(3) (whose
representations are labelled by the angular momentum quantum numbers,
and
), where they are
simply the
symbols
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- 29
- http://cpc.cs.qub.ac.uk/cpc/cgi-bin/showversions.pl/?catid=acry
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- 30
- Eqn
16 for SO, and 25-27 for CF, and reproduced in more modern notation in appendix C
of [52]
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- 31
- Eqns 66 for the conversion of the Racah parameters to Slater
integrals, 63 for the
operator, 69 for
, 73-74 for
, and 78, 28 and 80-87 for
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- 32
- Eqn 7-58
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- 33
- Depending on the Java setup on your computer, a conflict may occur between the McPhase
Java programs and other Java programs, such as the Matlab GUI. If you find that no graphics
windows open, and have other Java programs running in the background, try to close all other Java programs.
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- 34
- in princpiple it is possible
to go beyond this approximation, this would involve an inversion of the complete phonon
dynamics, i.e. all
... this has not been programmed
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- 35
- Note that table 6-1 and equ 6-7 are not correct in this reference.
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- 36
- Note that these conditions are essential and put a limit to the
applicability of the theory, for example in the case of charge transfer excitations from
one subsystem to the next [73].
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- 37
- the
on top of
indicates matrix notation
for
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- 38
- supplementary material - screen
shot movie comparing the speed of traditional Green's function method and DMD
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- 39
- In case
of magnetic order. In general this will be the unit cell of
the Bravais lattice in section M, which
is a superlattice of the crystal lattice.
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- 40
- using the appropriate
expression for the matrix elements of of the scattering
operator as given in [32, equ. (11.86) or (11.87b)].
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