CaSnN2

Data files related to CaSnN2 paper Ilteris K. Turan and Walter R. L. Lambrecht.

The data files directly related to each figure and table are in the folder Data files.

In Data files:

1. Fig.1 is a .vesta file for the crystal structure which can be opened with the VESTA software available at https://jp-minerals.org/vesta/en/download.html
2. Fig.2 contain the QSGW^BSE band structure files in the format of bnds.ext used in the Questaal suite which are described at https://www.questaal.org/docs/input/data_format/ To make the plots in the paper, these data files are processed using the plbnds code available at: https://www.questaal.org/docs/misc/plbnds/ Data related to energies listed in Table II can also be exctracted from here. Note that this data is given in units of Ry.
3. Fig.3 is the Partial density of states within QSGW^BSE, a .agr file generated using xmgrace https://plasma-gate.weizmann.ac.il/Grace/ . They can also be used with https://sourceforge.net/projects/qtgrace/ . It contains the data sets for each xy curve internally.
4. The data for Fig.4 are provided in three parts:

1. Independent particle approximation (IPA) (orange dashed line). Data contains columns for photon energy, and next \epsilon_2 in a,b,c polarizations.
2. Bethe-Salpeter Equation (orange solid line). Data contains multiple columns, first is the photon energy, next are the blocks of real and imaginary parts of \epsilon in independent particle approx. (e_1p) and BSE solutions (e) along a,b,c, and [111] polarizations. We used the data for the BSE solution only along a,b,c polarizations. Note that this indep. particle solutions (e-1p) also includes the same broadening parameter (eta=0.005 Ry) of the BSE solution and we did not use them.
3. The value of QSGW^BSE band gap (vertical black line) can be read from the bands file as in Fig. 2.

5. Data for Fig.5 are in .h5 format are given in nine parts for each of the \lambda=1,...,9 exciton band weights. Each .h5 file includes bands, "b"; reciprocal lattice vectors "plat", weighted bands "wb". Their visualization could be done using the python code, "band-plot", which is a part of the Questaal suite. Please refer to https://www.questaal.org/docs/code/userguide/ for how to generate and plot the exciton weighted bands.
6. Data for Fig. 6 are the lbse output files listing the exciton energy levels obtained for N_kN_kN_k meshes with N_k=4,5,6,8,10. We used the lambda=1 values and the linear extrapolation could be performed in any preferable way. We used the interp1d function from the scipy.interpolate library in Python. We must note that for N_k=5 calculation we used N_v=15, N_c=13, whereas other meshes use N_v=5, N_c=1; but this is of no concern since the \lambda=1 exciton is purely from VBM to CBM.
7. Fig.7 data files is in .xsf format, are too large for Github and not included available upon request.

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Additionally:

• Band structure files for GGA-G0W0-QSGW^RPA are provided for band gap data given in Table I.
• Effective mass tensor components and principal axis data for Table III are provided in the folder Table III-eff_mass for the top six valence bands and bottom three conduction bands.
• The lbse file contatining exciton energies and oscillator strengths along a,b,c, and [111] polarizations for the calculation with N_v=15, N_c=13, eta=0.005 Ry within a 5x5x5 mesh is provided again for reference to Table IV.
• Abinit folder includes the static and high-frequency results for the dielectric function as well as the meta file (.abi). The details of the phonon calculation will be presented elsewhere.

In Meta files:

The Meta Files folder contains Questaal source files with settings for how the data were generated for each system ctrl, site, syml (for ΓXSYΓZURTZ path), and basp files are available for Questaal users.