Cd Si relaxation: Difference between revisions

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Description: relax the internal coordinates of a perturbed cd Si structure.
{{Template:Bulk_systems - Tutorial}}


----
== Task ==
*{{TAG|INCAR}}
System = diamond Si
ISTART = 0 ; ICHARG=2
ENCUT  =   240
ISMEAR = 0; SIGMA = 0.1;
NSW    =  5; IBRION =  2
ISIF  =  2


*{{TAG|KPOINTS}}
Relaxation of the internal coordinates of a perturbed cd Si structure.
k-points
 
  0
== Input ==
Monkhorst Pack
  11 11 11
  0  0  0


*{{TAG|POSCAR}}
=== {{TAG|POSCAR}} ===
  cubic diamond
  cubic diamond
     5.5
     5.5
Line 28: Line 18:
   0.125  0.125  0.130
   0.125  0.125  0.130


== Used INCAR Tags ==
*Break of symmetry in standard diamond structure: change z position from 0.125 to 0.130.
{{TAG|ENCUT}}, {{TAG|IBRION}}, {{TAG|ICHARG}}, {{TAG|ISIF}}, {{TAG|ISMEAR}}, {{TAG|ISTART}}, {{TAG|NSW}}, {{TAG|SIGMA}}, {{TAG|SYSTEM}}
 
=== {{TAG|INCAR}} ===
{{TAGBL|System}} = diamond Si
{{TAGBL|ISTART}} = 0 ; {{TAGBL|ICHARG}}=2
{{TAGBL|ENCUT}} =    240
{{TAGBL|ISMEAR}} = 0; {{TAGBL|SIGMA}} = 0.1;
{{TAGBL|NSW}}    =  10; {{TAGBL|IBRION}} =  2
{{TAGBL|ISIF}}  =  2
{{TAGBL|EDIFFG}} = -0.0001
 
*10 relaxation steps ({{TAG|NSW}}=10).
*Conjugate-gradient algorithm ({{TAG|IBRION}}=2).
*Relaxation only of internal parameters ({{TAG|ISIF}}=2).
 
=== {{TAG|KPOINTS}} ===
k-points
  0
Monkhorst Pack
  11 11 11
  0  0  0
 
== Calculation ==
 
*Example output after 10 relaxation steps:
POSITION                                      TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
      4.81253      4.81253      4.81250        -0.000724    -0.000724    -0.000031
      0.68747      0.68747      0.68750        0.000724      0.000724      0.000031
-----------------------------------------------------------------------------------
    total drift:                                0.000000      0.000000      0.000000
 
*Files to watch during relaxations:
**stdout (terminal): each electronic step is written to the terminal:
**{{TAG|OSZICAR}}: a copy of the terminal output.
**{{TAG|OUTCAR}}: more detailed information on every electronic and ionic step.
 
*Other important files:
**{{TAG|CONTCAR}}: holds the structure of the last ionic step and at the end the structural result (also very important for restarting a relaxation).
**{{TAG|STOPCAR}}: stops a relaxation.


== Download ==
== Download ==
[http://www.vasp.at/vasp-workshop/examples/diamondSirel.tgz diamondSirel.tgz]
[[Media:DiamondSirel.tgz| diamondSirel.tgz]]
----
[[VASP_example_calculations|To the list of examples]] or to the [[The_VASP_Manual|main page]]
{{Template:Bulk_systems}}
 
Back to the [[The_VASP_Manual|main page]].


[[Category:Examples]]
[[Category:Examples]]

Latest revision as of 08:33, 14 November 2019

Task

Relaxation of the internal coordinates of a perturbed cd Si structure.

Input

POSCAR

cubic diamond
   5.5
 0.0    0.5     0.5
 0.5    0.0     0.5
 0.5    0.5     0.0
  2
Direct
 -0.125 -0.125 -0.125
  0.125  0.125  0.130
  • Break of symmetry in standard diamond structure: change z position from 0.125 to 0.130.

INCAR

System = diamond Si
ISTART = 0 ; ICHARG=2
ENCUT  =    240
ISMEAR = 0; SIGMA = 0.1;
NSW    =  10; IBRION =  2
ISIF   =  2
EDIFFG = -0.0001
  • 10 relaxation steps (NSW=10).
  • Conjugate-gradient algorithm (IBRION=2).
  • Relaxation only of internal parameters (ISIF=2).

KPOINTS

k-points
 0
Monkhorst Pack
 11 11 11
 0  0  0

Calculation

  • Example output after 10 relaxation steps:
POSITION                                       TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
     4.81253      4.81253      4.81250        -0.000724     -0.000724     -0.000031
     0.68747      0.68747      0.68750         0.000724      0.000724      0.000031
-----------------------------------------------------------------------------------
   total drift:                                0.000000      0.000000      0.000000
  • Files to watch during relaxations:
    • stdout (terminal): each electronic step is written to the terminal:
    • OSZICAR: a copy of the terminal output.
    • OUTCAR: more detailed information on every electronic and ionic step.
  • Other important files:
    • CONTCAR: holds the structure of the last ionic step and at the end the structural result (also very important for restarting a relaxation).
    • STOPCAR: stops a relaxation.

Download

diamondSirel.tgz

Back to the main page.