... | ... | @@ -5,6 +5,7 @@ title: KKRSusc Quickstart Guide |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
# Perform a KKRsusc calculation
|
|
|
|
|
|
In order to investigate spin-excitations via the KKRsusc program please
|
... | ... | @@ -26,7 +27,7 @@ program. |
|
|
|
|
|
- To perform a susceptibility calculation, a detailed description of the region around the Fermi level is needed. For that reason the impurity cluster needs to be converged on a new contour, that includes energy points at $E_F$ and goes down to the real axis.
|
|
|
- To create the contour, use the [meshpanels.dat file](kkrsusc/meshpanels.dat). Substitute the Fermi energy with the one for your system, and run the `emesh.x` executable, included in the KKRSusc package. This will result in a file called [emesh.dat file](kkrsusc/emesh_dat) that includes the energy points of the contour.
|
|
|
- Finally do one iteration to write out the kkrflex_* files for a list of complex energy points as provided by the [emesh.dat file](kkrsusc/emesh_dat). In order to use this file you have to set the [run option](jumu/runoption) ''KKRSUSC '' in the inputcard. Futhermore, increase the `BZDIVIDE` (usually a `BZDIVIDE` of 500x500x1 for thin films is sufficient), and increase the `RCLUSTZ` parameter (usually to 2.5 is enough)
|
|
|
- Finally do one iteration to write out the kkrflex_* files for a list of complex energy points as provided by the [emesh.dat file](kkrsusc/emesh_dat). In order to use this file you have to set the [run option](jumu/runoption) ''KKRSUSC '' in the inputcard. Futhermore, increase the
|
|
|
|
|
|
## Step 3: Get the Impurity potential
|
|
|
|
... | ... | @@ -61,7 +62,7 @@ To calculate the self-energy and renormalised spectrum of the system, a fitting |
|
|
- Use the file [emesh.dat](emesh.dat), that describes an energy contour from $-0.3$ to $1.3Ry$ to run one iteration using the host code with the run flag KKRSUSC like in step 2.
|
|
|
- Similarly to the susceptibility calculation in step 4, two runs of the code are needed.
|
|
|
- Set `lfit= T` to instruct the code to run the fitting procedure and set the numerator polynomial degree `numd` and denominator degree `dend` to proper values, with $dend=numd +1$, to match the $1/\omega$ behaviour of the susceptibility in high frequencies. A typical range for `numd` is between 10-30, with the best fits usually in the region of 17-21.
|
|
|
- Set the bias voltage range (`vbiasmin`, `vbiasmax`) to match the frequency range defined by `omegamin, omegamax` and the corresponding parameters described in [newinpsusc.dat](newinpsusc.dat).
|
|
|
- Set the bias voltage range (`vbiasmin`, `vbiasmax`) to match the frequency range defined by `omegamin`, `omegamax` and the corresponding parameters described in [newinpsusc.dat](newinpsusc.dat).
|
|
|
- Run the mpi version of the code with `lhdio= T` and `lrestart= F` and `ldos= T` so that the DOS is calculated as well.
|
|
|
- Next perform the serial run with `lhdio= F` and `lrestart= T`
|
|
|
- After the calculation is done, plot the dos and compare it with the one you get from the impurity code. The goal here is to get a fit as loyal as possible.
|
... | ... | |