lwk205 / qeirreps Goto Github PK

# Copyright (c) 2020 Akishi Matsugatani, Seishiro Ono, Yusuke Nomura, Haruki Watanabe

======================================

Here, qeirreps is the root directory.

1. See the section "Preparation" in this document to install Quantum Espresso and qe2respack.
2. Go to "src" to compile qeirreps. See src/README_src.txt for detailed information.
3. See the section "Usage" in this document to know how to use qeirreps.
4. See "example", "example/README_ex.txt", and each example directory. They work as the tutorials.
5. See "reference" and "reference/README_ref.txt" to confirm the results.

======================================

# Contents

src:
The source directory. The Fortran 90 program "qeirreps.f90" is here.
See src/README_src.txt for compilation.

example:
The directory to store the example files.
There are some input files for calculation by QE, qe2respack, and qeirreps.
See example/README_ex.txt for detailed information.

reference:
The directory to store the reference files. 
One can check the result of calculation in example directories.
See reference/README_ref.txt for detailed information.

pseudo:
The directory to store the files of pseudo potential.
See pseudo/README_psd.txt for detailed information.


======================================

# Preparation

In order to use qeirreps, you need Quantum Espresso (QE) and qe2respack.
Here, we introduce how to get and install these applications.

1. Install Quantum Espresso (QE) for DFT calculation of the target material.
   See "https://www.quantum-espresso.org/".

   The version of QE should be qe-6.3 or before. 
   The later versions do not support the following option.
   
   When you compile QE, use the following option.
   
   ./configure --enable-xml=no
   
   This option is necessary to construct the input file of "qeirreps" through "qe2respack".
   It enables qe2respack to use iotk toolkits.

2. Install qe2respack to prepare input files of qeirreps from the output of QE.
   See the branch of respack "maxime2" in GitHub repository "https://github.com/mnmpdadish/respackDev/tree/maxime2" to get qe2respack.
   qe2respack is in "util/qe2respack/".
   
   REMARK: This program qe2respack belongs to the program package RESPACK (https://sites.google.com/view/kazuma7k6r).
           For the latest version of RESPACK, qe2respack does not support DFT calculation with spin-orbit coupling.
           For the usage of qeirreps, please use the specific version obtained as above.

   See "README.txt" in that directory.
   Edit "Makefile" to specify the compiler, libraries, and the location of QE.
   Type "make" to compile qe2respack.


The limitation for version of QE and the dependence on qe2respack will be improved in future update.

======================================


# Usage

Here, we introduce how to use qeirreps.
The example directory is also helpful as tutorial. See "example/README_ex.txt" and each example directory for more information.


1. Preparing input files of qeirreps

   qeirreps works based on the output of QE. To prepare the input files of qeirreps, the following three steps are needed to be done one by one:

1-1. Self-consistent first-principles (scf) calculation of a target material.
1-2. Non-self-consistent first-principles (nscf) calculation of the material for each high-symmetry momentum.
1-3. Data conversion from QE output files to qeirreps input files.

1-1 and 1-2: carried out by the original functions of QE.
   The wavefunction data will be produced in the directory OUTDIR/PREFIX.save which specified in input files of QE.
   
   REMARK:
   Norm-conserving calculations are necessary.
   Set the option "wf_collect = .TRUE."
   Use the pseudo potentials optimized for norm-conserving calculations. See "pseudo\README_psd.txt" for detailed information.

1-3: carried out by qe2respack.
   The output files in OUTDIR/PREFIX.save should be converted by qe2respack into the form of input files of qeirreps.
   Go to the work directory (referred to as "DIRECTRY_NAME" in the following).
   Create a directory named "dir-wfn" if it does not exist. 
   Type as follows at the directory "DIRECTORY_NAME".

   $ PATH_OF_qe2respack/qe2respack OUTDIR/PREFIX.save

   "PATH_OF_qe2respack" is the directory which has executable file of qe2respack.
   "OUTDIR/PREFIX.save" is the directory produced by QE in step 1-2.

   Eight files including "dat.wfn" will be generated in the directory "dir-wfn". qeirreps reads these files in step 2.


2. Running qeirreps 

   Go to the work directory (referred to as "DIRECTRY_NAME" in 1-3).
   Create a directory named "output" if it does not exist. 
   Run qeirreps by typing as 

   $ PATH_OF_qeirreps/qeirreps.x DIRECTORY_NAME

   "PATH_OF_qeirreps" is the location of the qeirreps executable file.
   "DIRECTORY_NAME" is the directory referred in 1-3, which contains "dir-wfn" and "output".

   Some text files will be exported in "output", for example, "character.dat".
   Check the document and files in reference directory for more information.

   For materials with inversion symmetry, qeirreps can also evaluate the Z4 index.
   An option of filling should be added to the command as 

   $ PATH_OF_qeirreps/qeirreps.x DIRECTORY_NAME FILLING

   "FILLING" is the number of electrons per unit cell of the target material.
   This filling is shown in the standard output of scf calculation by QE as "number of electrons = FILLING".

   Z4 index will be exported as "z4.dat" in the directory "output".
 

======================================