CdSe半导体band gap计算不正确

zifei · 发表于 Post on 2020-10-19 23:03:28

希望计算CdSe半导体的band gap，添加三维周期性条件后得到的为0.64eV，扩大晶胞变化也不是很大。请问老师是什么参数设置错了吗？输入文件如下
&GLOBAL
PROJECT CdSe-pdos
RUN_TYPE ENERGY
PRINT_LEVEL MEDIUM
&END GLOBAL

&FORCE_EVAL
METHOD Quickstep
STRESS_TENSOR ANALYTICAL

&DFT
   BASIS_SET_FILE_NAME  BASIS_MOLOPT
   POTENTIAL_FILE_NAME  GTH_POTENTIALS

   &QS
   WF_INTERPOLATION ASPC
   EXTRAPOLATION_ORDER 1
   &END QS

&MGRID
   CUTOFF 400
&END MGRID

   &POISSON
      PERIODIC XYZ
      POISSON_SOLVER PERIODIC
   &END POISSON

   &SCF
      SCF_GUESS ATOMIC
      EPS_SCF 1.0E-6
      MAX_SCF 300
      &OT T
      PRECONDITIONER FULL_SINGLE_INVERSE
      MINIMIZER DIIS
      LINESEARCH 3PNT
      &END OT
   &END SCF

   &XC
      &XC_FUNCTIONAL PBE
      &END XC_FUNCTIONAL
   &END XC

   &PRINT
      &MO_CUBES
      WRITE_CUBE F
      NHOMO 5
      NLUMO 5
      &END MO_CUBES
      &PDOS
      NLUMO 5
      &END
   &END PRINT

&END DFT

&SUBSYS
   &CELL
      ABC [angstrom] 6.050000 6.050000 6.050000
      PERIODIC XYZ
      MULTIPLE_UNIT_CELL 1 1 1
   &END CELL
   &TOPOLOGY
      MULTIPLE_UNIT_CELL 1 1 1
   &END TOPOLOGY
   &COORD
      SCALED
         Se 0.25000 0.25000 0.25000
         Se 0.75000 0.75000 0.25000
         Se 0.75000 0.25000 0.75000
         Se 0.25000 0.75000 0.75000
         Cd 0.00000 0.00000 0.00000
         Cd 0.00000 0.50000 0.50000
         Cd 0.50000 0.00000 0.50000
         Cd 0.50000 0.50000 0.00000
   &END
   &KIND Cd
      ELEMENT Cd
      BASIS_SET DZVP-MOLOPT-SR-GTH
      POTENTIAL GTH-PBE-q12
   &END KIND
   &KIND Se
      ELEMENT Se
      BASIS_SET DZVP-MOLOPT-SR-GTH
      POTENTIAL GTH-PBE-q6
   &END KIND

&END SUBSYS

&END FORCE_EVAL

zifei · 发表于 Post on 2020-10-20 14:49:23

我找到原因了。。。bulk CdSe的band gap大概就是这个范围。

喵星大佬 · 发表于 Post on 2020-10-20 23:41:22

扩大晶胞本来也不会改变能带结构，完了你还要反折叠回去，还不如就用元胞

算能带别用cp2k，又慢又不好用，QE他不香么。。。

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[CP2K] CdSe半导体band gap计算不正确