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qe计算软件 (qe计算参数设置)

🏷️ 学术之友LUCK ✍️ 北京理工大学博士 📅 2026-03-14T19:39:24+00:00

说明：以二维InSe原胞为例，QE版本：qe-6.4.1，赝势：SSSP。

1. 结构优化

通过Materials studio 2018的建模功能切出二维InSe原胞，如图所示，并导出为InSe.cif格式。

qes怎么计算,qe工艺流程公式

二维InSe原胞

使用VESTA软件打开InSe.cif文件，然后File→Export Date，保存格式选择vasp，原子坐标选择Fractional coordinates，最后点击确定。

2、QE输入文件结构

QE的结构优化主要使用的是pw.x模块，该模块包含非常多的输入参数，建议在计算过程中逐步学习，无需一次性学完所有命令，即使学完也是徒劳，因为几乎无法记住。

结构优化在QE中是比较诟病的一个地方，优化速度非常慢，对于大体系实现结构优化是非常慢的，如果计算的体系包含较多的原子，建议使用VASP。QE结合EPW计算材料的与声子有关的性质比较合适，且这类计算一般不需要建立超胞，能够达到计算目的。总之，根据计算的任务和目的合理选择第一性原理计算软件是比较明智的。

2.1 pw.x模块输入文件结构

&CONTROL
...
/
&SYSTEM
...
/
&ELECTRONS
...
/
[ &IONS
...
/ ]
[ &CELL
...
/ ]
ATOMIC_SPECIES
X Mass_X PseudoPot_X
Y Mass_Y PseudoPot_Y
Z Mass_Z PseudoPot_Z
ATOMIC_POSITIONS { alat | bohr | crystal | angstrom | crystal_sg }
X 0.0 0.0 0.0 {if_pos(1) if_pos(2) if_pos(3)}
Y 0.5 0.0 0.0
Z O.0 0.2 0.2
K_POINTS { tpiba | automatic | crystal | gamma | tpiba_b | crystal_b | tpiba_c | crystal_c }
if (gamma)
 nothing to read
if (automatic)
 nk1, nk2, nk3, k1, k2, k3
if (not automatic)
 nks
 xk_x, xk_y, xk_z, wk
[ CELL_PARAMETERS { alat | bohr | angstrom }
 v1(1) v1(2) v1(3)
 v2(1) v2(2) v2(3)
 v3(1) v3(2) v3(3) ]
[ OCCUPATIONS
 f_inp1(1) f_inp1(2) f_inp1(3) ... f_inp1(10)
 f_inp1(11) f_inp1(12) ... f_inp1(nbnd)
[ f_inp2(1) f_inp2(2) f_inp2(3) ... f_inp2(10)
 f_inp2(11) f_inp2(12) ... f_inp2(nbnd) ] ]
[ CONSTRAINTS
 nconstr { constr_tol }
 constr_type(.) constr(1,.) constr(2,.) [ constr(3,.) constr(4,.) ] { constr_target(.) } ]
[ ATOMIC_FORCES
 label_1 Fx(1) Fy(1) Fz(1)
 .....
 label_n Fx(n) Fy(n) Fz(n) ]

2.2 二维InSe原胞结构优化输入文件

&CONTROL
calculation='vc-relax', ! vc-relax | relax
restart_mode='from_scratch', ! normal used
prefix='InSe', ! prepended to input/output filenames
pseudo_dir='../pseudo/', ! directory containing pseudopotential files
outdir='../tmp/', ! input, temporary, output files are found in this directory
forc_conv_thr=1d-5, ! forces convergence threshold 1d-03
/
&SYSTEM
ibrav = 0 ! Bravais-lattice index 
nat=4 ! number of atoms in the unit cell
ntyp=2 ! number of types of atoms in the unit cell 
ecutwfc=60.0, ! kinetic energy cutoff (Ry) for wavefunctions 
ecutrho=720.0, ! Kinetic energy cutoff (Ry) for charge density
/
&ELECTRONS
mixing_beta=0.7, ! mixing factor for self-consistency
conv_thr=1d-8, ! Convergence threshold for selfconsistency 1d-6
/
&IONS
ion_dynamics='bfgs', ! Specify the type of ionic dynamics
/
&CELL
cell_dynamics='bfgs', ! Specify the type of dynamics for the cell
press=0.0, ! 
press_conv_thr=0.5, ! Convergence threshold on the pressure for variable cell
cell_dofree=2Dxy, ! for 2D materials
/
CELL_PARAMETERS {angstrom} ! specify the structure
 4.0836000443 0.0000000000 0.0000000000
 -2.0418000221 3.5365013772 0.0000000000
 0.0000000000 0.0000000000 25.3775005341
ATOMIC_SPECIES ! 
In 114.80 In.pbe-dn-rrkjus_psl.0.2.2.UPF
Se 78.960 Se_pbe_v1.uspp.F.UPF
ATOMIC_POSITIONS {crystal}
In 0.333333347 0.666666695 0.555589958
In 0.333333347 0.666666695 0.444410042
Se 0.666666674 0.333333347 0.394049989
Se 0.666666674 0.333333347 0.605950011
K_POINTS automatic
12 12 1 0 0 0

2.3 结构优化的经验总结

pw.x模块用于结构优化时，对于体系的对称性非常敏感，也就是QE自身不会寻找体系的对称性，只能依靠手动输入体系的对称性，这点与VASP相比是非常欠缺的，因为VASP是可以自己寻找对称性的。对于二维InSe原胞，有对称性与无对称性的结构优化使用时间相差了近５倍。

查看优化所用时间

grep PWSCF InSe.vc-relax.out | tail -n 1

输入对称性

 PWSCF : 4m10.53s CPU 4m51.82s WALL

没有输入对称性

 PWSCF : 21m5.53s CPU 4m51.82s WALL

对于离子的受力，一般使用准牛顿迭代算法

ion_dynamics='bfgs'

pwscf模块做结构优化时，对于二维材料无需重新编译软件，即可做到不优化真空层，这点比VASP方便，具体设置如下

cell_dofree CHARACTER
Default: 'all'
Select which of the cell parameters should be moved: 
'all' :
all axis and angles are moved 
'ibrav' :
all axis and angles are moved, but the lattice but be representable with the initial ibrav choice 
'x' :
only the x component of axis 1 (v1_x) is moved 
'y' :
only the y component of axis 2 (v2_y) is moved 
'z' :
only the z component of axis 3 (v3_z) is moved 
'xy' :
only v1_x and v2_y are moved 
'xz' :
only v1_x and v3_z are moved 
'yz' :
only v2_y and v3_z are moved 
'xyz' :
only v1_x, v2_y, v3_z are moved 
'shape' :
all axis and angles, keeping the volume fixed 
'volume' :

the volume changes, keeping all angles fixed (i.e. only celldm(1) changes)
'2Dxy' :
only x and y components are allowed to change 
'2Dshape' :
as above, keeping the area in xy plane fixed 
'epitaxial_ab' :
fix axis 1 and 2 while allowing axis 3 to move 
'epitaxial_ac' :
fix axis 1 and 3 while allowing axis 2 to move 
'epitaxial_bc' :
fix axis 2 and 3 while allowing axis 1 to move 
BEWARE: if axis are not orthogonal, some of these options do not work symmetryisbroken. If you are not happy with them, edit subroutine init_dofree in file Modules/cell_base.f90

3、结构自洽计算

3.1 输入文件

&CONTROL
 calculation='scf',
 restart_mode='from_scratch',
 prefix='InSe',
 pseudo_dir='../pseudo/',
 outdir='../tmp/',
/
&SYSTEM
 ibrav = 0
 nat=4
 ntyp=2
 ecutwfc=60.0,
 ecutrho=480.0,
/
&ELECTRONS
 mixing_beta=0.7,
 conv_thr=1d-8,
/
CELL_PARAMETERS {angstrom}
 4.081910567 0.000000000 0.000000000
 -2.040955283 3.535038247 0.000000000
 0.000000000 0.000000000 25.377500534
ATOMIC_SPECIES
 In 114.80 In.pbe-dn-rrkjus_psl.0.2.2.UPF
 Se 78.960 Se_pbe_v1.uspp.F.UPF
ATOMIC_POSITIONS {crystal}
In 0.333333347 0.666666695 0.555619036
In 0.333333347 0.666666695 0.444380964

Se 0.666666674 0.333333347 0.394016400
Se 0.666666674 0.333333347 0.605983600
K_POINTS automatic
12 12 1 0 0 0


mpirun -np 16 pw.x < InSe.scf.in.$ecutwfc > InSe.scf.out.$ecutwfc


grep -e 'kinetic-energy cutoff' -e ! InSe.scf.out.$ecutwfc | \
 awk '/kinetic/{ecutwfc=$(NF-1)}/!/{print ecutwfc, $(NF-1)}' >> InSe.etot_vs_ecutwfc


done

3.2 ecutwfc测试

for ecutwfc in 50 55 60 65 70 75 80 ; do

# self-consistent calculation
cat > InSe.scf.in.$ecutwfc << EOF
&CONTROL
 calculation='scf',
 restart_mode='from_scratch',
 prefix='InSe',
 pseudo_dir='../pseudo/',
 outdir='../test_tmp/',
/
&SYSTEM
 ibrav = 0
 nat=4
 ntyp=2
 ecutwfc=$ecutwfc,
 ecutrho=$((8*$ecutwfc)),
/
&ELECTRONS
 mixing_beta=0.7,
 conv_thr=1d-8,
/
CELL_PARAMETERS {angstrom}
 4.081910567 0.000000000 0.000000000
 -2.040955283 3.535038247 0.000000000
 0.000000000 0.000000000 25.377500534
ATOMIC_SPECIES
 In 114.80 In.pbe-dn-rrkjus_psl.0.2.2.UPF
 Se 78.960 Se_pbe_v1.uspp.F.UPF
ATOMIC_POSITIONS {crystal}
In 0.333333347 0.666666695 0.555619036
In 0.333333347 0.666666695 0.444380964

Se 0.666666674 0.333333347 0.394016400
Se 0.666666674 0.333333347 0.605983600
K_POINTS automatic
12 12 1 0 0 0
EOF

测试结果：

qes怎么计算,qe工艺流程公式

encut

3.3 kpoints测试

for kpoints in 4 6 8 10 12 14 16 18 20 ; do

# self-consistent calculation
cat > InSe.scf.in.$kpoints << EOF
&CONTROL
 calculation='scf',
 restart_mode='from_scratch',
 prefix='InSe',
 pseudo_dir='../pseudo/',
 outdir='../test_tmp/',
/
&SYSTEM
 ibrav = 0
 nat=4
 ntyp=2
 ecutwfc=70,
 ecutrho=840,
/
&ELECTRONS
 mixing_beta=0.7,
 conv_thr=1d-8,
/
CELL_PARAMETERS {angstrom}
 4.081910567 0.000000000 0.000000000
 -2.040955283 3.535038247 0.000000000
 0.000000000 0.000000000 25.377500534
ATOMIC_SPECIES
 In 114.80 In.pbe-dn-rrkjus_psl.0.2.2.UPF
 Se 78.960 Se_pbe_v1.uspp.F.UPF
ATOMIC_POSITIONS {crystal}
In 0.333333347 0.666666695 0.555619036
In 0.333333347 0.666666695 0.444380964

Se 0.666666674 0.333333347 0.394016400
Se 0.666666674 0.333333347 0.605983600
K_POINTS automatic
$kpoints $kpoints 1 0 0 0
EOF

mpirun -np 16 pw.x < InSe.scf.in.$kpoints > InSe.scf.out.$kpoints

echo -e "$kpoints \c" >> InSe.etot_vs_kpoints
grep ! InSe.scf.out.$kpoints | \
 awk '/!/{print $(NF-1)}' >> InSe.etot_vs_kpoints

done

测试结果：

qes怎么计算,qe工艺流程公式

kpoints

3.4 结构自洽计算总结

通过对ecutwfc和kpoints的测试，我们选定ecutwfc的值为80 Ry，kpoints的值为８ ８ 1，用这个值返回去重新优化结构和自洽，然后开始计算下面的性质。

4、能带计算

4.1 输入文件

&CONTROL
 calculation='bands',
 restart_mode='from_scratch',
 prefix='InSe',
 pseudo_dir='../pseudo/',
 outdir='../tmp/',
 verbosity='high',
/
&SYSTEM
 ibrav = 0
 nat=4
 ntyp=2
 ecutwfc=80.0,
 ecutrho=960.0,
 nbnd=26,
/
&ELECTRONS
 mixing_beta=0.7,
 conv_thr=1d-8,
/
CELL_PARAMETERS {angstrom}
 4.085963663 -0.000000000 0.000000000
 -2.042981832 3.538548331 0.000000000
 0.000000000 0.000000000 25.377500534
ATOMIC_SPECIES
 In 114.80 In.pbe-dn-rrkjus_psl.0.2.2.UPF
 Se 78.960 Se_pbe_v1.uspp.F.UPF
ATOMIC_POSITIONS {crystal}
In 0.333333347 0.666666695 0.555623200
In 0.333333347 0.666666695 0.444376800
Se 0.666666674 0.333333347 0.394099781
Se 0.666666674 0.333333347 0.605900219
 K_POINTS crystal_b
4
0.5 0.0 0.0 100 !M
0.0 0.0 0.0 100 !G
0.33333 0.33333 0.0 100 !K
0.5 0.0 0.0 100 !M

4.2 后处理文件band2.in文件

&bands
prefix='InSe',
outdir='../tmp/',
filband='InSebands.dat',
lsym=.true.
/

4.3 画能带图的后处理程序plotband.x

> plotband.x InSebands.dat
Reading 26 bands at 301 k-points
file with representations not compatible with bands
Range: -16.4500 5.4820eV Emin, Emax > -4 4
high-symmetry point: 0.5000 0.2887 0.0000 x coordinate 0.0000
high-symmetry point: 0.0000 0.0000 0.0000 x coordinate 0.5774
high-symmetry point: 0.3333 0.5773 0.0000 x coordinate 1.2440
high-symmetry point: 0.5000 0.2887 0.0000 x coordinate 1.5773
output file (gnuplot/xmgr) > InSebands.plot
bands in gnuplot/xmgr format written to file InSebands.plot 
output file (ps) > InSebands.ps
Efermi > -1.5444
deltaE, reference E (for tics) 2 -1.5444
bands in PostScript format written to file InSebands.ps

说明：QE自带的画图程序plotband.x画出的能带图几乎无法直接用于文章中，因此这步处理意义不大。可以直接使用band.x计算出的InSebands.dat.gnu文件，通过origin等专业的绘图软件绘制能带图。

能带图计算结果：

qes怎么计算,qe工艺流程公式

2D_InSe-band_qe

本文章转载自贺勇个人博客，请大家多多关注，有非常多的干货！

qes怎么计算,qe工艺流程公式

链接: https://yh-phys.github.io/2019/10/11/qe-band/

5、其它QE入门教程友情链接

(1) https://yyyu200.github.io/DFTbook/

(2) http://blog.sciencenet.cn/u/pfliu89

(3) http://blog.sciencenet.cn/u/yhli0906