vasp计算光学性质教程_性质_光学

文章目录 [+]

材料光学性子(介电函数)的由下面第一个式子描述，而对应的实部和虚部由后面两个公式给出(更多参数详情请阅读VASPKIT英文文章，https://arxiv.org/abs/1908.08269，如利用了干系功能务必帮我们引用，感谢！
)：

二维材料光学性子打算的理论公式如下：

截图来源：DOI: 10.1021/acsnano.9b06698

本文以二维InSe材料(晶体构造如下所示)为例，详细先容了二维InSe的光学性子打算过程。

截图来源：Nanoscale, 2018, 10, 11441–11451.

2、构造优化

INCAR

SYSTEM = 2D_InSeISTART = 0NWRITE = 2 PREC = AccurateENCUT = 500GGA = PENSW = 200ISIF = 3ISYM = 2NBLOCK = 1 KBLOCK = 1IBRION = 2NELM = 80 EDIFF = 1E-05EDIFFG = -0.01 ALGO = NormalLDIAG = .TRUE.LREAL = .FALSE.ISMEAR = 0SIGMA = 0.02ICHARG = 2LPLANE = .TRUE.NPAR = 4LSCALU = .FALSE.NSIM = 4LWAVE = .FALSE.LCHARG = .FALSE.ICORELEVEL = 1

POSCAR

2D_InSe1.04.0836000443 0.0000000000 0.0000000000-2.0418000221 3.5365013772 0.00000000000.0000000000 0.0000000000 25.3775005341In Se2 2Direct0.666670026 0.333330010 0.5899799920.666670026 0.333330010 0.4787899680.333329978 0.666669998 0.4284399860.333329978 0.666669998 0.640340007

KPOINTS

Monkhorst Pack of Gamma centered0Gamma 13 13 1 0.0 0.0 0.0

POTCAR

cat In_d/POTCAR Se/POTCAR > POTCAR

OPTCELL

100110000

3、静态自洽

INCAR

SYSTEM = 2D_InSeISTART = 0NWRITE = 2PREC = AccurateENCUT = 500GGA = PE NSW = 0ISIF = 2ISYM = 2NBLOCK = 1KBLOCK = 1IBRION = -1NELM = 80EDIFF = 1E-05EDIFFG = -0.01ALGO = NormalLDIAG = .TRUE.LREAL = .FALSE.ISMEAR = 0SIGMA = 0.02ICHARG = 2LPLANE = .TRUE.NPAR = 4LSCALU = .FALSE.NSIM = 4LWAVE = .TRUE.LCHARG = .TRUE.ICORELEVEL = 1

POSCAR

cp CONTCAR POSCAR

KPOINTS

自洽打算哀求有密的k网格点，在打算条件许可的情形下哀求自洽的k网格点大致为优化时的2倍旁边。

Monkhorst Pack of Gamma centered0Gamma 25 25 1 0.0 0.0 0.0

4、光学性子打算

INCAR

SYSTEM = 2D_InSeISTART = 1NWRITE = 2PREC = AccurateENCUT = 500GGA = PENSW = 0ISIF = 2ISYM = 2NBLOCK = 1KBLOCK = 1IBRION = -1NELM = 80EDIFF = 1E-05EDIFFG = -0.01ALGO = NormalLDIAG = .TRUE.LREAL = .FALSE.ISMEAR = 0SIGMA = 0.02ICHARG = 11LPLANE = .TRUE.NPAR = 4LSCALU = .FALSE.NSIM = 4LWAVE = .FALSE.LCHARG = .FALSE.LOPTICS = .TRUE.NBANDS = 72NEDOS = 2000CSHIFT = 0.1

KPOINTS

Monkhorst Pack of Gamma centered0Gamma 29 29 1 0.0 0.0 0.0

Note：对付光学性子的打算，也便是打算材料的介电函数，须要足够多的空带和致密的k网格点，使其达到非常好的收敛状态，我们才可以得到合理的光学性子；因此常日打算中，一样平常设置NBANDS为默认值(可在自洽的OUTCAR中以关键字NBANDS查找到)的2-3倍，k网格点为自洽值或适当增加。

别的的POSCAR、POTCAR不变，并哀求有WAVECAR和CHGCAR文件，以供读取。

5、数据处理

利用optics.sh脚本(脚本内容如下，VASPKIT1.0以上版本已经不须要单独运行此文件，可以直接运行711功能得到光学干系数据)得到介电函数的实部和虚部。

# extract image and real parts of dielectric function from vasprun.xmlawk 'BEGIN{i=1} /<imag>/,\ /<\/imag>/ \ {a[i]=$2 ; b[i]=$3 ; c[i]=$4; d[i]=$5 ; e[i]=$6 ; f[i]=$7; g[i]=$8; i=i+1} \ END{for (j=12;j<i-3;j++) print a[j],b[j],c[j],d[j],e[j],f[j],g[j]}' vasprun.xml > IMAG.in#awk 'BEGIN{i=1} /imag/,\# /\/imag/ \# {a[i]=$2 ; b[i]=$3 ; c[i]=$4; d[i]=$5 ; e[i]=$6 ; f[i]=$7; g[i]=$8; i=i+1} \# END{for (j=12;j<i-3;j++) print a[j],b[j],c[j],d[j],e[j],f[j],g[j]}' vasprun.xml > IMAG.inawk 'BEGIN{i=1} /<real>/,\ /<\/real>/ \ {a[i]=$2 ; b[i]=$3 ; c[i]=$4; d[i]=$5 ; e[i]=$6 ; f[i]=$7; g[i]=$8; i=i+1} \ END{for (j=12;j<i-3;j++) print a[j],b[j],c[j],d[j],e[j],f[j],g[j]}' vasprun.xml > REAL.in

利用vaspkit-1.00后处理软件得到光学性子(详细公式见下面)：

$ vaspkit-1.00 \\\/// / _ _ \ Hey, you must know what you are doing. (| (.)(.) |) Otherwise you might get wrong results!+-----.OOOo----oOOO.------------------------------------------+| VASPKIT Version: 1.00 (16 Sep. 2019) || A Pre- and Post-Processing Program for VASP Code || Core Developers: Vei WANG, Nan XU, Jin-Cheng LIU || Please send Bugs and Suggestions to vaspkit@gmail.com |+-----.oooO-----------------------------------------------------+ Oooo. \ ( \_) ) / (_/===================== Structural Options ========================1) VASP Input Files Generator 2) Elastic-Properties3) K-Path Generator 4) Structure Editor5) Catalysis-ElectroChemi Kit 6) Symmetry Search===================== Electronic Options ========================11) Density-of-States 21) DFT Band-Structure23) 3D Band-Structure 25) Hybrid-DFT Band-Structure26) Fermi-Surface 28) Band-Structure Unfolding=========== Charge & Potential & Wavefunction Options ===========31) Charge & Spin Density 42) Potential-Related51) Wave-Function Analysis====================== Misc Utilities ===========================71) Optical-Properties 72) Molecular-Dynamics Kit73) VASP2BoltzTraP Interface91) Semiconductor Calculator 92) 2D-Materials Kit0) Quit------------>>71============================ Optical Options ====================711) Linear Optical Spectrums712) Transition Dipole Moment at Single Kpoint713) Transition Dipole Moment for Band-Structure716) Total Joint Density of States717) Partial Joint Density of States0) Quit9) Back------------>>711+-------------------------- Warm Tips --------------------------+ See an example in vaspkit/examples/Si_bse_optical. This module is NOT suitable for low-dimensional materials.+---------------------------------------------------------------+===================== Energy Unit ===============================Which Energy Unit Do You Want to Adopt?1) eV2) nm3) THz------------>>1-->> (01) Reading IMAG.in and REAL.in Files...-->> (02) Written Optical Files Succesfully!+---------------------------------------------------------------+| DISCLAIMER || Check the Consistency of Your Results if Necessary || Any Suggestions for Improvements are Welcome || (^.^) GOOD LUCK (^.^) ||---------------------------------------------------------------|| We Would Appreciate if You Cite in Your Research with VASPKIT.|| Ref: V. Wang, N. Xu, J.C. LIU, G. Tang, et al, VASPKIT: A Pre-|| and Post-Processing Program for VASP Code, arXiv:1908.08269. |+---------------------------------------------------------------+

截图来源：arXiv:1908.08269 (VASPKIT英文文章).

得到的光学性子包括：光接管系数ABSORB.dat

#energy xx(cm^-1) yy(cm^-1) zz(cm^-1) xy(cm^-1) yz(cm^-1) zx(cm^-1)0.000 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+000.020 0.3820E+00 0.3820E+00 0.5428E+00 0.0000E+00 0.0000E+00 0.0000E+000.040 0.1415E+01 0.1415E+01 0.2057E+01 0.0000E+00 0.0000E+00 0.0000E+000.060 0.3268E+01 0.3268E+01 0.4714E+01 0.0000E+00 0.0000E+00 0.0000E+000.080 0.5885E+01 0.5885E+01 0.8238E+01 0.0000E+00 0.0000E+00 0.0000E+000.100 0.9265E+01 0.9265E+01 0.1301E+02 0.0000E+00 0.0000E+00 0.0000E+000.120 0.1307E+02 0.1307E+02 0.1885E+02 0.0000E+00 0.0000E+00 0.0000E+000.141 0.1792E+02 0.1792E+02 0.2540E+02 0.0000E+00 0.0000E+00 0.0000E+000.161 0.2353E+02 0.2353E+02 0.3336E+02 0.0000E+00 0.0000E+00 0.0000E+000.181 0.2990E+02 0.2990E+02 0.4240E+02 0.0000E+00 0.0000E+00 0.0000E+000.201 0.3701E+02 0.3702E+02 0.5250E+02 0.0000E+00 0.0000E+00 0.0000E+000.221 0.4431E+02 0.4431E+02 0.6369E+02 0.0000E+00 0.0000E+00 0.0000E+000.241 0.5290E+02 0.5290E+02 0.7596E+02 0.0000E+00 0.0000E+00 0.0000E+000.261 0.6223E+02 0.6223E+02 0.8927E+02 0.0000E+00 0.0000E+00 0.0000E+000.281 0.7233E+02 0.7234E+02 0.1037E+03 0.0000E+00 0.0000E+00 0.0000E+00