Presentation on theme: "Tutorial for Elasticity tool (1) Select (2) Depress For speed, an elastic calculation should be preceded by a careful optimization of atom coordinates."— Presentation transcript:
Tutorial for Elasticity tool (1) Select (2) Depress For speed, an elastic calculation should be preceded by a careful optimization of atom coordinates in the experimental cell data. pyrite Select
VASP interface dialog The k-mesh suggestion and info is implemented in the same way as for ABINIT For the various options, consult the VASP manual e.g. at: http://cms.mpi.univie.ac.at/vasp/vasp/vasp.html Select If unsure, select the first potential The suggestion was 3x3x3, which would be OK for an insulator, but sulfides border on the metallic behaviour. The k-mesh was accordingly upped to 5x5x5.
INCAR is proposed for editing Fine-tune the VASP execution flags for your exact purposes Echoes for questions asked
optimization constraints are implemented This is an easy case because the material is cubic P. Centered cubics, tetragonals etc. are a lot less trivial. The user is relieved from all this tedium.
The PostProc.bat file Toth utility context import relaxed structure with total energy into JOBreport.out import stress
Double-click A DOS window appears. VASP is running. Start the execution
The DOS window disappears Execute PostProc.bat: JobReport.out grows by 1 kB Double-click JobReport.out grows by 1kB
JobReport now contains the optimized crystallographic description for pyrite. Lets import it. Select Depress
Tutorial for Elasticity tool (1) Select (2) Depress
Last chance to modify engine selection. Type This is the only elasticity-related info required for a successful elasticity run If unsure, just click OK. You will not get the fastest nor the most precise results, but a compromise.
VASP interface dialog is purely about individual optimizations The k-mesh suggestion and info is implemented in the same way as for ABINIT For the various options, consult the VASP manual e.g. at: http://cms.mpi.univie.ac.at/vasp/vasp/vasp.html All the elastic- related data is processed in the background Suggestion was 3x3x3. Increase a bit because pyrite is not truly an insulator. Depress If in doubt, dont alter. It may not be fast, but it will get there.
Numerous POSCARXX input data files have been created, one for each distortion
The JOBreport.out file contains data on the distortions used
Many output files have appeared Double-click. JOBreport increases by 3 kB
Least squares analysis has been run in the background symmetry constraints on elastic coefficients least squares analysis of quantum results Experimental values: Simmons & Birch (1963) C11 381.8 GPa C12 31.0 C44 109.4
The matrix laid out numerically. Hexagonal cases may not be as trivial as this one. Negative diagonal elements would mean that the phase is not stable. equivalent isotropic coefficients speed of sound Debye temperature Bulk, shear, Youngs coefficients etc.. have been extracted.
copy to clipboard with then transfer to view property screen Now produce radial plots of elasticity
Paste into the Property dialog paste type Depress
Radial plot of the small shear coefficient in pyrite