Misplaced Fermi Level

[gVallverdu]

Hi all,

I tried to perform a simple DOS calculation on bulk Cu2O. I did all calculation with PAW-PBE pseudopotential, at ENCUT = 520. The CONTCAR file after a full relaxation of the system is the following.

Code: Select all

Cu2O?hexagonal??????????????????????????
???1.00000000000000?????
?????6.0389999999999997????0.0000000000000000????0.0000000000000000
????-3.0194999999999999????5.2298999999999998????0.0000000000000000
?????0.0000000000000000????0.0000000000000000????7.3959999999999999
??12???6
Direct
??0.0000000000000000??0.0000000000000000??0.0000000000000000
??0.5000000000000000??0.0000000000000000??0.0000000000000000
??0.0000000000000000??0.5000000000000000??0.0000000000000000
??0.5000000000000000??0.5000000000000000??0.0000000000000000
??0.3333330000000032??0.1666669999999968??0.3333330000000032
??0.8333330000000032??0.1666669999999968??0.3333330000000032
??0.3333330000000032??0.6666669999999968??0.3333330000000032
??0.8333330000000032??0.6666669999999968??0.3333330000000032
??0.1666669999999968??0.3333330000000032??0.6666669999999968
??0.6666669999999968??0.3333330000000032??0.6666669999999968
??0.1666669999999968??0.8333330000000032??0.6666669999999968
??0.6666669999999968??0.8333330000000032??0.6666669999999968
??0.5000000000000000??0.0000000000000000??0.2500000000000000
??0.5000000000000000??0.0000000000000000??0.7500000000000000
??0.1666669999999968??0.3333330000000032??0.4166669999999968
??0.1666669999999968??0.3333330000000032??0.9166669999999968
??0.8333330000000032??0.6666669999999968??0.0833330000000032
??0.8333330000000032??0.6666669999999968??0.5833330000000032

I would like to compute the DOS of this system. I thus did a single point calculation and next a DOS calculation. Hereafter are the INCAR files

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Single?Point
Electronic?minimization
??PREC?=?High
??EDIFF?=?1e-6
??ENCUT?=?520.0
??ISYM?=?0

Ionic?relaxation
??NSW?=?0

DOS
??ISMEAR?=?-5

I copy CHGCAR and WAVECAR output files of the single point into the directory where I did the DOS calculation.

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DOS?calculation
Electronic?minimization
??PREC?=?High
??EDIFF?=?1e-6
??ENCUT?=?520.0
??ISYM?=?0
??LORBIT?=?11
??ICHARG?=?11

Ionic?relaxation
??NSW?=?0

DOS
??ISMEAR?=?-5

I obtain a DOS with a good shape and a gap of about 0.8 eV. But the fermi energy written in the DOSCAR or OUTCAR file correspond to the beginning of unoccupied bands instead of the end of occupied bands. If I look at the integrated DOS, the number of electron is reached for the end of the occupied bands thus I do not understand why the fermi energy is wrong.

I performed the same calculations with a +U approximation with these parameters in the INCAR file, but I obtained the same results.

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+U
LDAU?=?.TRUE.
LDAUTYPE?=?2
LDAUL?=?2?-1
LDAUU?=?7.50?0.00
LDAUJ?=?0.98?0.00
LDAUPRINT?=?2
LMAXMIX?=?4

Thanks for your help

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