# ABINIT, DMFT input variables:

## List and description.

This document lists and provides the description of the name (keywords) of the "DMFT" input variables to be used in the main input file of the abinit code.

##### Copyright (C) 1998-2017 ABINIT group (DCA,XG,RC,YG,FJ)

### Content of the file : alphabetical list of "DMFT" variables.

A.
B.
C.
D. dmft_dc dmft_entropy dmft_iter dmft_mxsf dmft_nlambda dmft_nwli dmft_nwlo dmft_rslf dmft_solv dmft_t2g dmft_tolfreq dmft_tollc dmftbandf dmftbandi dmftcheck dmftctqmc_check dmftctqmc_correl dmftctqmc_gmove dmftctqmc_grnns dmftctqmc_meas dmftctqmc_mov dmftctqmc_mrka dmftctqmc_order dmftctqmc_triqs_nleg dmftqmc_l dmftqmc_n dmftqmc_seed dmftqmc_therm

dmft_dc
Mnemonics: Dynamical Mean Fied Theory: Double Counting
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [10/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 1

Value of double counting used for DMFT. Only value 1 is activated for the moment and is the FLL double counting.

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dmft_entropy
Mnemonics: Dynamical Mean Fied Theory: ENTROPY
Executable: abinit
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {v7:[29,30,31]}.
Variable type: integer
Default is 0
Only relevant if usedmft==1 and dmft_solv==5

If 1, enable the calculation of the entropy within the DMFT framework and so allows the calculation of the total energy (free energy). In the current implementation, this is only possible with dmft_solv=5 (Continuous Time Quantum Monte Carlo). See also the input variable dmft_nlambda.

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dmft_iter
Mnemonics: Dynamical Mean Fied Theory: number of ITERation
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [20/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0

Number of iterations for the DMFT inner loop.

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dmft_mxsf
Mnemonics: Dynamical Mean Fied Theory: MiXing parameter for the SelF energy
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [15/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: real
Default is 0.3

Mixing parameter for the simple mixing of the self-energy.

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dmft_nlambda
Mnemonics: Dynamical Mean Fied Theory: Number of LAMBDA points
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {v7:[29,30,31]}.
Variable type: integer
Default is 6
Only relevant if usedmft==1 and dmft_entropy==1

dmft_nlambda gives the number of integration points for the thermodynamical integration in case of free energy calculation within DMFT. Its value must be greater or equal to 3.

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dmft_nwli
Mnemonics: Dynamical Mean Fied Theory: Number of frequency omega (W) in the LInear mesh
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [20/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0

Number of Matsubara frequencies (linear mesh)

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dmft_nwlo
Mnemonics: Dynamical Mean Fied Theory: Number of frequency omega (W) in the LOg mesh
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [18/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0

Number of frequencies in the log mesh.

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dmft_rslf
Mnemonics: Dynamical Mean Fied Theory: Read SeLF energy
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [15/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0

Flag to read/write Self-Energy. If put to one, self-energy is written and read at each DFT iteration.

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dmft_solv
Mnemonics: Dynamical Mean Fied Theory: choice of SOLVer
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [19/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: real
Default is 5

Choice of solver for the Impurity model.

- 0=> No solver and U=0, J=0 (see upawu and jpawu).
- 1=> LDA+U self-energy is used (for testing purpose)
- 2=> Hubbard one solver. The Hubbard one solver is an approximation which gives a rough description of correlated Mott insulators. It should not be used for metals.
- 5=> Use the Continuous Time Quantum Monte Carlo (CTQMC) solver CT-Hyb of ABINIT in the density density representation, CTQMC calculations are much more time consuming that Hubbard I calculations. Nevertheless, the calculation is fully parallelised.
- 6=> Continuous Time Quantum Monte Carlo (CTQMC) solver CT-Hyb of TRIQS in the density density representation.
- 7=> Continuous Time Quantum Monte Carlo (CTQMC) solver CT-Hyb of TRIQS with the rotationally invariant formulation.

The CT Hyb algorithm is described in Phys. Rev. Lett 97, 076405, (2006) . For a discussion of density-density approximation with respect with the rotationnally invariant formulation, see e.g. Phys. Rev. B 86, 155107 (2012) .
The ABINIT/CT Hyb implementation is discussed in http://dx.doi.org/10.1016/j.cpc.2016.04.003 .
The TRIQS/CT Hyb implementation is described in Comp. Phys. Comm. 200, 274 (2016) . Before using it, it has to be installed following instructions at https://triqs.ipht.cnrs.fr/1.x/install.html. Starting from release 8.6.0, the interface is valid only for TRIQS 1.4 and TRIQS/CTHYB 1.4. An example of a config .ac file to compile ABINIT with TRIQS can be found in ~/doc/build/config-examples/ubu_gnu_4.9_triqs.ac.
See the useful variables for CT-QMC solver : dmftctqmc_basis, dmftctqmc_check, dmftctqmc_correl, dmftctqmc_gmove, dmftctqmc_grnns, dmftctqmc_meas, dmftctqmc_mrka, dmftctqmc_mov, dmftctqmc_order, dmftctqmc_triqs_nleg, dmftqmc_l, dmftqmc_n, dmftqmc_seed, dmftqmc_therm
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dmft_t2g
Mnemonics: Dynamical Mean Fied Theory: t2g orbitals
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [6/907] in abinit tests, [1/136] in tuto abinit tests. Test list: {paral:[99],tutoparal:[dmft_2],v7:[27,30,31],v8:[01]}.
Variable type: integer
Default is 0

Can be set to 1 only if in cubic symmetry. It enables one to carry a DFT+DMFT calculations only on t2g orbitals.

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dmft_tolfreq
Mnemonics: Dynamical Mean Fied Theory: TOLerance on DFT correlated electron occupation matrix for the definition of the FREQuency grid
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [2/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[99],v8:[01]}.
Variable type: real
Default is 0.0001

The LDA occupation matrix for correlated electrons can be computed directly. It can be compared to the calculation of the same quantity using LDA Green's function, a sum over Matsubara frequencies and a projection over correlated orbitals. Because the Matsubara grid is finite, the two quantities differ. If this difference is larger than dmft_tolfreq, then the code stops and an error message is given.

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dmft_tollc
Mnemonics: Dynamical Mean Fied Theory: TOLerance on Local Charge for convergence of the DMFT loop
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [1/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {v6:[45]}.
Variable type: real
Default is 1e-05

Tolerance for the variation of Local Charge during iterations of the DMFT Loop.
The default value is good for fast calculations. However, to obtain good convergence of the DFT Loop, the DMFT Loop needs a better convergence criterion.

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dmftbandf
Mnemonics: Dynamical Mean Field Theory: BAND: Final
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [21/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0

dmftbandf is the last band taken into account in the Projected Local Orbitals scheme of DFT+DMFT. With dmftbandi, they define the energy window used to define Wannier Functions. (see Amadon, B., Lechermann, F., Georges, A., Jollet, F., Wehling, T. O., and Lichtenstein, A. I. Phys. Rev. B 77(20), (2008).)

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dmftbandi
Mnemonics: Dynamical Mean Field Theory: BAND: Initial
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [21/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0

dmftbandi is the first band taken into account in the Projected Local Orbitals scheme of LDA+DMFT. With dmftbandf, they define the energy window used to define Wannier Functions. (see Amadon, B., Lechermann, F., Georges, A., Jollet, F., Wehling, T. O., and Lichtenstein, A. I. Phys. Rev. B 77(20), (2008).)

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dmftcheck
Mnemonics: Dynamical Mean Fied Theory: CHECKs
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [16/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0

Only for developer purposes. (Introduced by B. Amadon, v6.1.0)

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dmftctqmc_check
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo CHECK
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[92],v7:[28,29]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv==5

Check the fast calculations during the Monte Carlo simulation with very slow but robust methods. Should only be used for debugging.

- 0=> No check.
- 1=> Check the overlap calculations (Impurity operator).
- 2=> Check the update of M matrix calculation (Bath operator).
- 3=> Check both.

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dmftctqmc_correl
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo CORRELations
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[92],v7:[28,29]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv==5

Flag to compute statistics about segments and anti-segments during the simulation. Slow down the simulation.

- 0=> Nothing done
- 1=> Calculations performed and written in "Correlation.dat" file

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dmftctqmc_gmove
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo Global MOVEs
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [4/907] in abinit tests, [1/136] in tuto abinit tests. Test list: {paral:[92],tutoparal:[dmft_2],v7:[28,29]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv==5

Default is no global moves. The value of this variable is the modulo used to try a global move. A value of 5000 means that a global move is tried every 5000 Monte Carlo sweep.

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dmftctqmc_grnns
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo GReeNs NoiSe
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[92],v7:[28,29]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv==5

Compute the statistical noise for each time slice of each green function. This is a good approximation only if there is enough Monte Carlo sweeps per cpu.

- 0=> Nothing
- 1=> Do it and write the noise in the "Gtau.dat" file.

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dmftctqmc_meas
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo MEASurements
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[92],v7:[28,29]}.
Variable type: integer
Default is 1
Only relevant if dmft_solv==5

The modulo used to measure the interaction energy and the number of electrons. Example : 2 means the measure is perform every two sweeps.

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dmftctqmc_mov
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo MOVie
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[92],v7:[28,29]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv==5

Print a latex file per cpu displaying the full simulation. This option should only be use with very small number (<1000) of Monte Carlo sweeps since it requires a lot of I/O band width.

- 0=> Nothing
- 1=> Write the "Movie_id.dat" file where id is the MPI rank of each process

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dmftctqmc_mrka
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo MARKov Analysis
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [3/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[92],v7:[28,29]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv==5

Measure the time evolution of the number of electrons for each orbital and perform a fourier transform. The result can be plotted using the "Markov_id.dat" file

- 0=> Nothing
- 1=> Do it and write the noise in the "Markov_id.dat" file where id is the rank of each MPI process.

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dmftctqmc_order
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo perturbation ORDER
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [4/907] in abinit tests, [1/136] in tuto abinit tests. Test list: {paral:[92],tutoparal:[dmft_2],v7:[28,29]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv==5

Print a file containing the statistic distribution of the number of segments per orbital. The maximal order taken into account dmftctqmc_order : 50 means that we have the statistic distribution from 0 to 50 segments. The result is written in the "Perturbation.dat" file.

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dmftctqmc_triqs_nleg
Mnemonics: Dynamical Mean Fied Theory: Continuous Time Quantum Monte Carlo perturbation of TRIQS, Number of LEGendre polynomials
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [2/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {paral:[99],v8:[01]}.
Variable type: integer
Default is 30
Only relevant if dmft_solv==6 or 7

Specify the number of Legendre polynomials used for the calculation of Green's function in CTQMC code from the library TRIQS. Default is 30. The value of coefficients are given in file whose name ending is "Legendre_coefficient.dat". (see also Phys. Rev. B 84, 075145 (2010))

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dmftqmc_l
Mnemonics: Dynamical Mean Fied Theory: Quantum Monte Carlo time sLices
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [10/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: integer
Default is 0
Only relevant if dmft_solv>=4

Number of time slices used to represent the time green function. This value should be carefully chosen according to Niquist frequency and the tsmear value.

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dmftqmc_n
Mnemonics: Dynamical Mean Fied Theory: Quantum Monte Carlo Number of sweeps
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Moderately used: [10/907] in abinit tests, [1/136] in tuto abinit tests. Tuto test list: {tutoparal:[dmft_2]}.
Variable type: real
Default is 0.0
Only relevant if dmft_solv>=4

Number of Monte Carlo sweeps. Should be at least 10^6.

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dmftqmc_seed
Mnemonics: Dynamical Mean Fied Theory: Quantum Monte Carlo SEED
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [2/907] in abinit tests, [0/136] in tuto abinit tests. Test list: {v7:[28,29]}.
Variable type: integer
Default is jdtset
Only relevant if dmft_solv>=4

Seed to initilize the random number generator.
Should not be relevant except for testing purpose.
NOTE : If the CT-QMC (dmft_solv=5) is used on many CPUs, each CPU initializes its random number generator with dmftqmc_seed+rank where rank is the rank of the cpu in the MPI communicator.

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dmftqmc_therm
Mnemonics: Dynamical Mean Fied Theory: Quantum Monte Carlo THERMalization
Executable: abinit
Characteristic: DEVELOP
Mentioned in topic: DMFT.
Rarely used: [9/907] in abinit tests, [1/136] in tuto abinit tests. Test list: {paral:[92,99],tutoparal:[dmft_2],v7:[27,28,29,30,31],v8:[01]}.
Variable type: integer
Default is 1000
Only relevant if dmft_solv==5

Number of Monte Carlo sweeps for the thermalization

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