作者:谢炘玥,邮箱:xyxie@stu.pku.edu.cn
审核:陈默涵,邮箱:mohanchen@pku.edu.cn
最后更新时间:2025/03/04
我们已经测试过了一维材料的长边分别摆放在 XYZ 三个方向时,对计算效率的影响,并通过测试结果给出了建议,参考 ABACUS 如何选择晶胞朝向获得最佳并行效率?以碳纳米管为例 · GitBook。现在我们考虑一个二维六方氮化硼体系,即材料在两个方向的长度明显大于第三个方向。
下面我们分别将短边摆放在 X、Y、Z 方向,比较计算结果能量和时间来判断短边摆放方式对计算的影响。
本文算例的氮化硼在一个方向的长度明显小于另外两个方向,我们采用原子弛豫计算(ABACUS 中设置 calculation
为 relax
,只让原子移动而固定晶格常数)。同样,通过对 STRU
和 KPT
文件的三列进行轮换改变摆放方式。我们先来看看为 ABACUS 计算准备的 INPUT
、STRU
和 KPT
三个输入文件。
可以注意到,在本次计算中,我们使用了 kspacing
这个参数(Full List of INPUT Keywords — ABACUS documentation),可以根据晶胞大小自动生成 KPT
文件。因此不再需要我们手动调换 K 点的顺序。
INPUT_PARAMETERS
suffix BN
pseudo_dir ./
orbital_dir ./
calculation cell-relax
symmetry 0
basis_type lcao
ecutwfc 100
scf_thr 1e-07
scf_nmax 100
smearing_method gauss
smearing_sigma 0.002
mixing_type pulay
mixing_beta 0.3
cal_force 1
cal_stress 1
force_thr_ev 0.01
stress_thr 0.5
relax_nmax 100
out_stru 1
kspacing 0.08
在本体系中,B 和 N 原子各有 96 个,h-BN 结构图如下。
可以发现,此时短边在晶胞的 X 方向上。
ATOMIC_SPECIES
B 10.81 B_ONCV_PBE-1.0.upf
N 14.007 N_ONCV_PBE-1.0.upf
NUMERICAL_ORBITAL
B_gga_8au_100Ry_2s2p1d.orb
N_gga_8au_100Ry_2s2p1d.orb
LATTICE_CONSTANT
1.8897261258369282
LATTICE_VECTORS
2.6665300000 0.0000000000 0.0000000000
0.0000000000 16.970664000 0.0000000000
0.0000000000 0.0000000000 28.020088000
ATOMIC_POSITIONS
Direct
B
0.0000000000
96
0.0000000000 0.0126740000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.0768190000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.0481810000 1 1 1 mag 0.0
0.5000000000 0.1376740000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.2018190000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.1731810000 1 1 1 mag 0.0
0.0000000000 0.2626740000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.0768190000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.0481810000 1 1 1 mag 0.0
0.5000000000 0.3876740000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.2018190000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.1731810000 1 1 1 mag 0.0
0.0000000000 0.5126740000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.0768190000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.0481810000 1 1 1 mag 0.0
0.5000000000 0.6376740000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.2018190000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.1731810000 1 1 1 mag 0.0
0.0000000000 0.7626740000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.0768190000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.0481810000 1 1 1 mag 0.0
0.5000000000 0.8876740000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.2018190000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.1731810000 1 1 1 mag 0.0
0.0000000000 0.0126740000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.3268190000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.2981810000 1 1 1 mag 0.0
0.5000000000 0.1376740000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.4518190000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.4231810000 1 1 1 mag 0.0
0.0000000000 0.2626740000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.3268190000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.2981810000 1 1 1 mag 0.0
0.5000000000 0.3876740000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.4518190000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.4231810000 1 1 1 mag 0.0
0.0000000000 0.5126740000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.3268190000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.2981810000 1 1 1 mag 0.0
0.5000000000 0.6376740000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.4518190000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.4231810000 1 1 1 mag 0.0
0.0000000000 0.7626740000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.3268190000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.2981810000 1 1 1 mag 0.0
0.5000000000 0.8876740000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.4518190000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.4231810000 1 1 1 mag 0.0
0.0000000000 0.0126740000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.5768190000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.5481810000 1 1 1 mag 0.0
0.5000000000 0.1376740000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.7018190000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.6731810000 1 1 1 mag 0.0
0.0000000000 0.2626740000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.5768190000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.5481810000 1 1 1 mag 0.0
0.5000000000 0.3876740000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.7018190000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.6731810000 1 1 1 mag 0.0
0.0000000000 0.5126740000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.5768190000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.5481810000 1 1 1 mag 0.0
0.5000000000 0.6376740000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.7018190000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.6731810000 1 1 1 mag 0.0
0.0000000000 0.7626740000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.5768190000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.5481810000 1 1 1 mag 0.0
0.5000000000 0.8876740000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.7018190000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.6731810000 1 1 1 mag 0.0
0.0000000000 0.0126740000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.8268190000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.7981810000 1 1 1 mag 0.0
0.5000000000 0.1376740000 0.8750000000 1 1 1 mag 0.0
0.0000000000 0.1439860000 0.9518190000 1 1 1 mag 0.0
0.5000000000 0.0189860000 0.9231810000 1 1 1 mag 0.0
0.0000000000 0.2626740000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.8268190000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.7981810000 1 1 1 mag 0.0
0.5000000000 0.3876740000 0.8750000000 1 1 1 mag 0.0
0.0000000000 0.3939860000 0.9518190000 1 1 1 mag 0.0
0.5000000000 0.2689860000 0.9231810000 1 1 1 mag 0.0
0.0000000000 0.5126740000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.8268190000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.7981810000 1 1 1 mag 0.0
0.5000000000 0.6376740000 0.8750000000 1 1 1 mag 0.0
0.0000000000 0.6439860000 0.9518190000 1 1 1 mag 0.0
0.5000000000 0.5189860000 0.9231810000 1 1 1 mag 0.0
0.0000000000 0.7626740000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.8268190000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.7981810000 1 1 1 mag 0.0
0.5000000000 0.8876740000 0.8750000000 1 1 1 mag 0.0
0.0000000000 0.8939860000 0.9518190000 1 1 1 mag 0.0
0.5000000000 0.7689860000 0.9231810000 1 1 1 mag 0.0
N
0.0000000000
96
0.0000000000 0.0518080000 0.0478800000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.0771200000 1 1 1 mag 0.0
0.0000000000 0.1807370000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.1728800000 1 1 1 mag 0.0
0.0000000000 0.0518080000 0.2021200000 1 1 1 mag 0.0
0.5000000000 0.0557370000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.0478800000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.0771200000 1 1 1 mag 0.0
0.0000000000 0.4307370000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.1728800000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.2021200000 1 1 1 mag 0.0
0.5000000000 0.3057370000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.0478800000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.0771200000 1 1 1 mag 0.0
0.0000000000 0.6807370000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.1728800000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.2021200000 1 1 1 mag 0.0
0.5000000000 0.5557370000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.0478800000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.0771200000 1 1 1 mag 0.0
0.0000000000 0.9307370000 0.0000000000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.1728800000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.2021200000 1 1 1 mag 0.0
0.5000000000 0.8057370000 0.1250000000 1 1 1 mag 0.0
0.0000000000 0.0518080000 0.2978800000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.3271200000 1 1 1 mag 0.0
0.0000000000 0.1807370000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.4228800000 1 1 1 mag 0.0
0.0000000000 0.0518080000 0.4521200000 1 1 1 mag 0.0
0.5000000000 0.0557370000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.2978800000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.3271200000 1 1 1 mag 0.0
0.0000000000 0.4307370000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.4228800000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.4521200000 1 1 1 mag 0.0
0.5000000000 0.3057370000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.2978800000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.3271200000 1 1 1 mag 0.0
0.0000000000 0.6807370000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.4228800000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.4521200000 1 1 1 mag 0.0
0.5000000000 0.5557370000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.2978800000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.3271200000 1 1 1 mag 0.0
0.0000000000 0.9307370000 0.2500000000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.4228800000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.4521200000 1 1 1 mag 0.0
0.5000000000 0.8057370000 0.3750000000 1 1 1 mag 0.0
0.0000000000 0.0518080000 0.5478800000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.5771200000 1 1 1 mag 0.0
0.0000000000 0.1807370000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.6728800000 1 1 1 mag 0.0
0.0000000000 0.0518080000 0.7021200000 1 1 1 mag 0.0
0.5000000000 0.0557370000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.5478800000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.5771200000 1 1 1 mag 0.0
0.0000000000 0.4307370000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.6728800000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.7021200000 1 1 1 mag 0.0
0.5000000000 0.3057370000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.5478800000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.5771200000 1 1 1 mag 0.0
0.0000000000 0.6807370000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.6728800000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.7021200000 1 1 1 mag 0.0
0.5000000000 0.5557370000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.5478800000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.5771200000 1 1 1 mag 0.0
0.0000000000 0.9307370000 0.5000000000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.6728800000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.7021200000 1 1 1 mag 0.0
0.5000000000 0.8057370000 0.6250000000 1 1 1 mag 0.0
0.0000000000 0.0518080000 0.7978800000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.8271200000 1 1 1 mag 0.0
0.0000000000 0.1807370000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.1768080000 0.9228800000 1 1 1 mag 0.0
0.0000000000 0.0518080000 0.9521200000 1 1 1 mag 0.0
0.5000000000 0.0557370000 0.8750000000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.7978800000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.8271200000 1 1 1 mag 0.0
0.0000000000 0.4307370000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.4268080000 0.9228800000 1 1 1 mag 0.0
0.0000000000 0.3018080000 0.9521200000 1 1 1 mag 0.0
0.5000000000 0.3057370000 0.8750000000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.7978800000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.8271200000 1 1 1 mag 0.0
0.0000000000 0.6807370000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.6768080000 0.9228800000 1 1 1 mag 0.0
0.0000000000 0.5518080000 0.9521200000 1 1 1 mag 0.0
0.5000000000 0.5557370000 0.8750000000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.7978800000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.8271200000 1 1 1 mag 0.0
0.0000000000 0.9307370000 0.7500000000 1 1 1 mag 0.0
0.5000000000 0.9268080000 0.9228800000 1 1 1 mag 0.0
0.0000000000 0.8018080000 0.9521200000 1 1 1 mag 0.0
0.5000000000 0.8057370000 0.8750000000 1 1 1 mag 0.0
改变摆放方式时,要同时轮换 LATTICE_VECTORS
和 ATOMIC_POSITIONS
的顺序。
K_POINTS
0
Gamma
16 3 2 0 0 0
如前所述,该 KPT
文件是由 INPUT
文件里的 kspacing
参数所生成,因此不需要我们手动轮换,每次计算都会自动根据晶胞大小产生合适的 K 点。
计算采用 ABAUCS v3.8.0
版本,选择 64 个型号为 8426Y+
的 CPU 用 64 个进程对该二维氮化硼体系进行结构弛豫。下表给出本次测试的结果,将氮化硼的短边分别摆放在 XYZ 三个方向完成结构弛豫的步数都是 9 步。我们通过比较总能量和时间差异来判断摆放方式对计算结果的影响,可以看到系统总能量并不会受到短边取向的影响,但计算时间会受到显著影响。短边摆放在 Z 方向时,即两长边分别放在 X、Y 方向,计算时间明显慢于长边摆放在 Y、Z 和 Z、X 方向,每一电子步大概慢 6 s 左右。(注意:我们进行一维材料计算时,也建议将长边摆放在 Z 方向以提高计算效率)
h-BN 的两个长边方向 | 系统总能量 (eV) | 计算总时间 (s) | 计算总弛豫步数 | 运行一电子步的时间 (s) | FFT | UNIFORMGRID DIM(BIG) |
---|---|---|---|---|---|---|
XY | -33578.4871085887 | 2140 | 9 | 24.8~26.8 | 216*360*36 | 54*72*18 |
YZ | -33578.4871085889 | 1609 | 9 | 18.7~20.0 | 36*216*360 | 9*54*120 |
ZX | -33578.4871085888 | 1629 | 9 | 18.9~20.9 | 360*36*216 | 72*9*54 |
根据以上测试结果,建议读者们在进行二维体系计算时,将短边摆放在 X 或 Y 方向以获得 ABACUS 计算时的最大效率。