SmB6_XYmap_analysis

Code updated and uploaded on Jan 5 2022. Used in analysis published in Kotta et al., "Metallic chemical potentials in an insulating topological state."
For questions, or to request a set of demo ARPES data (.itx or .mat), email Erica Kotta at [email protected].

Goal: Create a Binning Series template, useful for analysing doping dependence.

Inputs:

• Spatial XY scan of ARPES measurement data

Outputs:

• 2d spatial maps of chemical potential (4f-orbital energy), surface termination (surf. Sm density), Kondo decoherence (4f-state lifetime), and sample surface topology (local geometrical tilt)
• GUI control of modeling parameters (limits of integration, binning series axes, etc)
• Plots of orbital energies doping dependence (5d- versus 4f-orbital energy)
• Plots of surface state Fermi momentum versus doping

Quick Start-Up Guide:

Save all files in this repository into the same folder, then run XYmap_gui.
Import mat --> Import Params --> Convert axes --> Run --> Map error --> Make BS --> Plot It (--> "Export BS")

Slightly more detailed instructions:

Save all files in this repository into the same folder, then run XYmap_gui.

If you don't already have an XY scan dataset saved into a mat file:

You can take a set of ARPES images, saved in the .itx format, saved into a folder that you specify within XYmap_gui.m script as variable data.itx_foldername and corresponding .csv file specified with data.csv_filename.
The .csv file contains XY scan metadata, listing the manipulator X,Y coordinates of each ARPES image in the folder of itx files.
Functions itx_csv_to_spec.m and csv_to_XY_list.m convert the dataset into a set of variables. You can now save these into a .mat file using the commented-out code located in the convertItx2Mat function inside the gui script.
Restart the gui with the new .mat file saved in the same folder.

If you already have the XY scan dataset saved into a mat file:

Select the mat file from the drop-down menu near the top of the gui and click the "Import mat" button.

If you need to set new parameters:

There is a set of default parameter values (FL E, BG E, ...) listed on the left hand side with default values for SmB6 spectral feature analysis.

• All parameters with "E" are energies, in units of kinetic energy.
• All paremeters with "th" are theta, units of degrees.
• All paremeters with "k" are momenta, units of inverse angstrom.

See XYmap_gui.m script for more descriptions of the parameters.
Click "Save" at bottom left to save the current set of parameter values into a new .mat file (name set same as mat file of spectral data with added "_params")
Click "Run" to run the feature map analysis code as defined in run_the_params.m script and produce a set of feature maps.

If you have a saved set of parameters from a previous run:

Click "Import params" to import the parameter set included in that .mat file.

To convert theta-->k or adjust geometry parameters:

Click "Convert axes" to convert to momenta with the specified experimental geometry parameters.

If you already have set of feature maps output from gui:

Click "Map error" button to calculate the standard deviation of each feature map, defined in the calculate_map_error.m script.
Click "Replot maps" to replot a figure of all the feature maps.

If you already have feature maps and map error calculations:

Select a feature in the drop-down menu at the bottom under "H axis" to set the spectral feature histogram that will be used to bin the dataset along the horizontal axis.
Type the number of bins you want to divide the horizontal axis histogram into in the window "Num bins" next to it.
If you want to further bin along a second axis, select another feature map in the drop-down menu under "V axis" and a number >1 in the "Num bins" next to it.
Click "Make BS" to plot a series of binned spectra partitioned along the horizontal and/or vertical axis as selected.
Select the "k-shift" option if you want to also add a k-correction to each individual spectrum before including into the binning series figure.