Supplemental data to the manuscript "Modelling the mean inner potential of alloyed and strained materials"

This is supplemental data to the manuscript "Modelling the mean inner potential of alloyed and strained materials". 

Motivation

The mean inner potential (MIP) is defined as the average Coulomb potential within a crystal, where the reference point for the Coulomb potential is set to zero in vacuum. It depends on the surface of the material and is sensitive to the redistribution of charge due to bonds in the crystal. Thus, it cannot be approximated with isolated atom data. The MIP for many semiconductors have been computed using density functional theory or measured experimentally using electron holography in the last years. However, values for alloyed and/or strained materials are not known or hardly reported. In the above mentioned work MIPs for strained GaP (uniaxially, biaxially and hydrostatically), alloyed but unstrained AlGaAs, InGaP and GeSi, as well as GeSi stressed to Si were computed with the Wien2k code.  Two prominent effects have been isolated: (1) The MIP behaves linear with concentration under alloying, if the volume stays constant. (2) The MIP scales with the ratio of the volumes before and after the volume change yielding a bowing of the MIP with concentration for alloyed materials. Both effects influence each other only negligibly.  The suggested model describes the computed data not perfectly but rather well compared to experimental precission.

Description of the files

The dataset uploaded here contains all structures used for the paper as well as the input files for Wien2k (version 24.1) computations as well as  V96.out files. The latter contain the evaluation of the Coulomb potentials and MIPs for the strained 1x1x1 slab models as well as 2x1x2 supercells for the unstrained AlGaAs, InGaP, GeSi as well as GeSi stressed to Si. They can be found in the files strain_111.tgz, AlGaAs_11_2.tgz, InGaP_11_2.tgz, GeSi_11_2.tgz and BiaxiallyStressedTernary_GeSi.tgz, respectively. Output of the Wien2k computations and Coulomb potentials in the cells were in the order of 200-500GB per material system and could not be uploaded due to memory limitations on Zenodo. They can be made available on special request. 

The go_lapw5.tgz files contains python and matlab scripts that were used for setting up the slabs and supercells as well for preparing and driving the output of the Coulomb potential from the Wien2k computation. A program integrate_from_rho reads the Coulomb potential and processes it to MIPs.  More details on the scripts as well as the workflow of the scripts are given in the Readme.txt files within the tarball go_lapw5.tgz. All scripts are meant to be executed from bash shell under linux and some will certainly fail to run under proprietary operating systems.  

The file ModelAmorphousCarbon.tgz contains the application of the proposed model to the density dependence of the MIP of amorphous carbon.