4. Preparation of initial structures for DFT calculations¶
4.1. mkposcar¶
- This program searches for symmetric operations and generates independent DFT structures.
- Generating high symmetric structures or random structures.
- Crystal lattice is determined by UPOSCAR and UPOTCAR files.
- Available only for binary systems.
- Available for multi-thread calculations using OPENMP.
Input files
Output files
- POSCAR_1 - POSCAR_nstruct
4.2. MKPOS.in¶
Example
Generating 5 structures with a lattice constructed by the 2x2x1 expansion of a 4-atoms unit cell (16-atoms cell). The structures have 12 A-atoms and 4 B-atoms.
ISUB = 1
NUCELL = 2 2 1
NCHANGE = 4
NSTRUCT = 5
SELECT = Highsym
4.2.1. ISUB tag¶
Sublattice indexes for considering atomic configurations. Atomic configurations are considered on ISUBth lattice sites of UPOSCAR (line 6).
- Default : 1
- Example : ISUB = 1 3
4.2.2. NUCELL tag¶
Independent atomic configurations are searched for on the lattice constructed by the NUCELL expansion of the unit cell.
- Default : none
- Example : NUCELL = 2 2 2
4.2.3. NCHANGE tag¶
Number of atoms. In N-nary systems, set N-1 kinds of atoms. The number of the other kind of atoms is automatically set to (number of lattice sites - NCHANGE).
- Default : none
- Example : NCHANGE = 6 2
4.2.5. SELECT tag¶
SELECT tag detemines how to generate structures.
- Default : Highsym
- SELECT = Highsym : generating high symmetric structures
- SELECT = Random : generating random structures
4.2.6. IOUT tag¶
- Default : 1
- 0 : POSCARs are not output.
- 1 : POSCARs are output.