Problem of using tetrahedron method

[Leon1999526]

Hello,
I am computing the properties of CsPbBr3 perovskite in tetragonal phase. The energy seems incorrect and I got this warning:

-----------------------------------------------------------------------------
| |
| W W AA RRRRR N N II N N GGGG !!! |
| W W A A R R NN N II NN N G G !!! |
| W W A A R R N N N II N N N G !!! |
| W WW W AAAAAA RRRRR N N N II N N N G GGG ! |
| WW WW A A R R N NN II N NN G G |
| W W A A R R N N II N N GGGG !!! |
| |
| Tetrahedron method does not include variations of the Fermi |
| occupations, so forces and stress will be inaccurate. We suggest |
| using a different smearing scheme ISMEAR = 1 or 2 for metals in |
| relaxations. |
| |
-----------------------------------------------------------------------------

And the following is my INCAR:

CsPbBr3-Cubic
ISTART = 0
ICHARGE = 2
LCHARG = .FALSE.
LWAVE = .FALSE.
ENCUT = 650
EDIFF = 1.00000E-8
ALGO = 48
NSW = 0
IBRION = 2
ISIF = 0
POTIM = 0.4
ISMEAR = -5
ISPIN = 1
NPAR = 6
LREAL = Auto
PREC = Accurate

Is there anything I can do to solve the problem?

[marie-therese.huebsch]

Hi,

Could you specify why the energy seems incorrect?

The warning says that ISMEAR = -5 cannot be used for calculations where you need accurate forces if states are close to the Fermi level. With IBRION = 2, you would, in principle, perform ionic relaxation using the conjugate gradient algorithm where accurate forces are required. But with NSW = 0 there will be zero ionic steps (so the setting IBRION = 2 is meaningless here).

Marie-Therese