Dipole corrections for defects in solids

• vaspwiki中相关的讨论Monopole Dipole and Quadrupole corrections 和 Dipole corrections for defects in solids
• 在计算带电杂质（或缺陷）的计算，通过设置 NELECT = 中性电子数 + 杂质的电荷量.
  • Note that NELECT does not have to be an integer
• Dipole corrections for defects in solids
  • 一般不需要做修正（总的误差约为0.1 eV），除非缺陷荷电量较大（绝对值2以上）、材料介电常数较小和cell尺寸较小
    • 如果体系够大以及所带的电荷在 +(-)2以内，不用考虑 Dipole Correction，因为此时Dipole Correction修正对体系的总能影响很小，对整个能级的影响很少. 如果是体系较小（原胞小）、杂质所带的电荷绝对值较大，需要考虑Dipole Correction.
  • 开启修正需要在INCRA添加

    IDPOL   = 4
    EPSILON = 1.0 #设置也无效，VASP只能手动scale down corrections.(不开启IDPOL，亦无效)
    LDIPOL  = .FALSE.

    • 仅对cubic cell完全修正（适用于chagred molecules in cubic box）
    • 修正仅对缺陷诱导的电荷波动局域化情形合理，即localized defect states
    • 需要手动用介电常数scaling down corrections
    • grep DIPCOR OUTCAR查看corrections信息
• hra's answer in  NEUTRAL & CHARGE DEFECTS
  "Bear in mind that once you change NELECT (or put a defect in your system), your eigenvalues are shifted, which requires further corrections. I prefer to figure out the potential alignment and image charge corrections by hand, and forget about built in tags like IDIPOL et al."
• 如何局域化缺陷电荷（Localizing Charge ）