计算能带自动产生k_VASP计算笔记-PBE能带计算及投影能带

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选择匿名的用户   2021-5-23 19:42   9200   0

35551e97c223a354f56b444462e55ab8.png

电子结构的计算流程

高对称点生成和后期处理使用vaspkit-1.1。

注:该方法主要使用原胞。

PBE能带计算流程

必要的文件

INCAR-scf
INCAR-band
KPOINTS
POTCAR
POSCAR #优化后的原胞
run_banddos.sh

run_banddos.sh的脚本设置如下:

#!/bin/bash

#优化后的初始POSCAR
cat > POSCAR <<!
Primitive Cell
  1.000000
    0.00000000000000    2.73423319845426    2.73423319845426
    2.73423319845426    0.00000000000000    2.73423319845426
    2.73423319845426    2.73423319845426    0.00000000000000
  Si
   2
DIRECT
    0.0000000000000000    0.0000000000000000    0.0000000000000000
    0.2500000000000000    0.2500000000000000    0.2500000000000000

!

cat > KPOINTS <<!
A
0
M
12 12 12
0  0  0
!

#基于seek-path自动生成高对称点
vaspkit -task 303
#得到KPATH.in 和 HIGH_SYMMETRY_POINTS 可以自行修改

cat > INCAR-scf <<!
ISTART=0
ICHARG=2
PREC=Accurate
GGA = PE
ADDGRID =.TRUE.

# Electronic relaxation
ENCUT=500
EDIFF=1E-8
EDIFFG=-0.001

ISMEAR=0
SIGMA = 0.05
POTIM=0.20

# Other Tags
#PSTRESS=

# Write flags
LWAVE=.TRUE.
LCHARG=.TRUE.
!

cat > INCAR-band <<!

Global Parameters
  ISTART =  1            (Read existing wavefunction; if there)
  ICHARG =  11            (Non-self-consistent: GGA/LDA band structures)
  LREAL  = F             (Projection operators: automatic)
  ENCUT  =  500          (Cut-off energy for plane wave basis set, in eV) 
  PREC   =  Accurate       (Precision level)  
  LWAVE  = .TRUE.        (Write WAVECAR or not)
  LCHARG = .TRUE.        (Write CHGCAR or not) 
  ADDGRID= .TRUE.        (Increase grid; helps GGA convergence) 
  # LVTOT  = .TRUE.      (Write total electrostatic potential into LOCPOT or not)
  # LVHAR  = .TRUE.      (Write ionic + Hartree electrostatic potential into LOCPOT or not)
  # NELECT =             (No. of electrons: charged cells; be careful)
  # LPLANE = .TRUE.      (Real space distribution; supercells)
  # NPAR   = 4           (Max is no. nodes; don't set for hybrids)

Electronic Relaxation
  ISMEAR =  0            (Gaussian smearing; metals:1)
  SIGMA  =  0.05         (Smearing value in eV; metals:0.2)
 # NELM   =  60           (Max electronic SCF steps)  
 # NELMIN =  4            (Min electronic SCF steps)
  EDIFF  =  1E-08       (SCF energy convergence; in eV) 
  GGA  =  PE             (PBEsol exchange-correlation)
  LORBIT=11              (plot projection band need to set)
  NEDOS = 2000

Ionic Relaxation
 # NELMIN =  6           (Min electronic SCF steps) 
  NSW    =  0            (Max electronic SCF steps)
  IBRION =  -1           (Algorithm: 0-MD; 1-Quasi-New; 2-CG)
  ISIF   =  2            (Stress/relaxation: 2-Ions, 3-Shape/Ions/V, 4-Shape/Ions)
  EDIFFG = -0.001         (Ionic convergence; eV/AA)
  #ISYM =  0              (Symmetry: 0=none; 2=GGA; 3=hybrids)

!

#自洽计算
cp INCAR-scf INCAR
echo "scf"; time mpirun -np 16 vasp_std
rm INCAR

#更换KPOINTS文件
cp KPATH.in KPOINTS
cp INCAR-band INCAR
echo "band"; time mpirun -np 16 vasp_std

#处理能带数据
vaspkit -task n #根据下面说明自行选择

### 211) Band-Structure
### 212) Projected Band-Structure for Selected Atom
### 213) Projected Band-Structure for Each Element
### 214) The Sum of Projected Band-Structure for Selected Atoms
### 215) Projected Band-Structure by Element Weight
###

运行后得到包含能带数据的dat文件

Si的能带图:

3edc1022b93f5d5ac96cbdd9c807ad14.png

Si的轨道投影能带:

929654466390d51d3d032475705edd14.png

态密度计算

注:与能带计算差不多,只是不需要修改K点。也可以直接用能带计算中得到的态密度。

必要的文件:

INCAR-scf
INCAR-dos
KPOINTS
POTCAR
run_dos.sh
#!/bin/bash

cat > POSCAR <<!
Primitive Cell
  1.000000
    0.00000000000000    2.73423319845426    2.73423319845426
    2.73423319845426    0.00000000000000    2.73423319845426
    2.73423319845426    2.73423319845426    0.00000000000000
  Si
   2
DIRECT
    0.0000000000000000    0.0000000000000000    0.0000000000000000
    0.2500000000000000    0.2500000000000000    0.2500000000000000

!

cat > KPOINTS <<!
A
0
M
21 21 21
0  0  0
!

cat > INCAR-scf <<!
ISTART=0
ICHARG=2
PREC=Accurate
GGA = PE
ADDGRID =.TRUE.

# Electronic relaxation
ENCUT=500
EDIFF=1E-8
EDIFFG=-0.001

ISMEAR=0
SIGMA = 0.05
POTIM=0.20

# Other Tags
#PSTRESS=

# Write flags
LWAVE=.TRUE.
LCHARG=.TRUE.
!

cat > INCAR-dos <<!

Global Parameters
  ISTART =  1            (Read existing wavefunction; if there)
  ICHARG =  11            (Non-self-consistent: GGA/LDA band structures)
  LREAL  = F             (Projection operators: automatic)
  ENCUT  =  500          (Cut-off energy for plane wave basis set, in eV) 
  PREC   =  Accurate       (Precision level)  
  LWAVE  = .TRUE.        (Write WAVECAR or not)
  LCHARG = .TRUE.        (Write CHGCAR or not) 
  ADDGRID= .TRUE.        (Increase grid; helps GGA convergence) 
  # LVTOT  = .TRUE.      (Write total electrostatic potential into LOCPOT or not)
  # LVHAR  = .TRUE.      (Write ionic + Hartree electrostatic potential into LOCPOT or not)
  # NELECT =             (No. of electrons: charged cells; be careful)
  # LPLANE = .TRUE.      (Real space distribution; supercells)
  # NPAR   = 4           (Max is no. nodes; don't set for hybrids)

Electronic Relaxation
  ISMEAR =  0            (Gaussian smearing; metals:1)
  SIGMA  =  0.05         (Smearing value in eV; metals:0.2)
 # NELM   =  60           (Max electronic SCF steps)  
 # NELMIN =  4            (Min electronic SCF steps)
  EDIFF  =  1E-08       (SCF energy convergence; in eV) 
  GGA  =  PE             (PBEsol exchange-correlation)
  LORBIT=11              (plot projection band need to set)
  NEDOS = 2000

Ionic Relaxation
 # NELMIN =  6           (Min electronic SCF steps) 
  NSW    =  0            (Max electronic SCF steps)
  IBRION =  -1           (Algorithm: 0-MD; 1-Quasi-New; 2-CG)
  ISIF   =  2            (Stress/relaxation: 2-Ions, 3-Shape/Ions/V, 4-Shape/Ions)
  EDIFFG = -0.001         (Ionic convergence; eV/AA)
  #ISYM =  0              (Symmetry: 0=none; 2=GGA; 3=hybrids)

!

#自洽计算
cp INCAR-scf INCAR
echo "scf"; time mpirun -np 16 vasp_std
rm INCAR

#更换KPOINTS文件
cp INCAR-dos INCAR
echo "dos"; time mpirun -np 16 vasp_std

vaspkit -task n #根据需要选择下面的参数,参照手册说明,有些需要给出元素,个数

### 111) Total Density-of-States                                     
### 112) Projected Density-of-States for Selected Atoms              
### 113) Projected Density-of-States for Each Element                
### 114) The Sum of Projected Density-of-States for Selected Atoms   
### 115) The Sum of Projected DOS for Selected Atoms and Orbitals    
### 116) Local Density-of-States for Each Element                    
### 117) Total Density-of-States with Adjustable Smearing Width

Si的band-dos图如下:

1363e7b9b64b0ef6eef74566dac5c6f2.png

二维材料1T-Tl2O的能带示例

PBE

1T-Tl2O的能带态密度:

a787141c1e4b64ce506c00de3d936666.png

1T-Tl2O的投影能带:

5b0545899a5b85e0213a7b217ddde17d.png

ccaeb0edfcd4c18e6dec8ce8b183e39c.png

1bd5be1634984334d3a77e49d3ec4658.png
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