[Wien] LSDA+U

[Igor Djerdj]

Dear all,
Few months ago I submitted the post here regarding the calculation of electronic structure of VOxHy compound. I followed advices which I got here related to chooice of RMTs, RKmax, etc.. and ended with compound which shows metallic behavior. According to DC conductivity measurement the investigated compound is semiconducting with bang gap of around 0.64 eV. Then I tried DFT calculation using LSDA+U approach, and obtained this time Fermi level just slightly below the top of valence band and the width of band gap strongly dependent of the value of U. For instance for U=0.6 eV Eg=2.1 eV, U=4 eV, Eg=0.7 eV. The question is about reliability of the applied method i.e. which value of U is recommendable for 3d electrons of V? There are also changes in DOS with the change of U.
Regards,
Igor
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