VASPKIT与量化软件 - 能带
type: channel
link: http://vaspkit.cn/index.php/tag/能带/
items: 3D能带计算
items: 杂化泛函计算能带
items: DFT能带计算

3D能带计算
type: item
date: 2021-12-01T18:49:00+08:00
description: 二维材料3D能带计算，这里以石墨烯为例，见vaspkit/examples/3D_band。 第一步，准备好石墨烯的POSCAR和用于静态计算的INCAR文件； 第二步：运行VASPKIT并选择231生成用于3D能带计算 的KPOINTS文件，执行界面如下所示。注意为了获得平滑的3D能带面，用于产生KPOINTS文件的分辨率值应该设置在0.005左右 ； -->> (01) Reading Structural Parameters from POSCAR File... +-------------------------- Warm Tips --------------------------+ * Accuracy Levels: (1) Medium: 0.02~0.01; (2) Fine: < 0.01; * 0.01 is Generally Precise Enough! +---------------------------------------------------------------+ Input the K-Spacing Value (in Unit of 2*PI/Angstrom): ------------>> 0.005 Reciprocal Lattice Vectors (in Units of 1/Angstrom): 2.5541403688 -1.4746336359 0.0000000000 2.5541403688 1.4746336359 0.0000000000 0.0000000000 0.0000000000 0.3192675461 Reciprocal Lattice Constants: 2.9493 2.9493 0.3193 Real-Space Lattice Constants: 2.4600 2.4600 19.6800 Size of K-Mesh: 96 96 1 -->> (2) Written KPOINTS File! 第三步，提交VASP作业； 第四步，待VASP计算完成后，再次运行VASPKIT，输入232或233命令。233命令可一次性输入包含价带顶的BAND.HOMO.grd和导带底的BAND.LUMO.grd文件的能带；232可以得到其它任意能带的计算数据，这里我们选择233，执行界面如下所示。 ------------>> 233 -->> (01) Reading Input Parameters From INCAR File... -->> (02) Reading Structural Parameters from POSCAR File... +---------------------------------------------------------------+ | >>> The Fermi Energy will be set to zero eV <<< | +---------------------------------------------------------------+ -->> (03) Reading Fermi-Energy from DOSCAR File... -->> (04) Reading Energy-Levels From EIGENVAL File... -->> (05) Written BAND_HOMO.grd File. -->> (06) Written BAND_LUMO.grd File. -->> (07) Written KX.grd and KY.grd Files. 第五步：运行python how_to_visual.py，绘制3D能带图(python2.7环境)。 如果3D能带图不够平滑，可通过能带插值进行改善。VASPKIT升级到1.3.0或更新版本，在~/.vaspkit文件中设置以下三个参数： GET_INTERPOLATED_DATA .TRUE. 是否插值 INTERPOLATION_SPACING 0.04 插值间距，决定平滑程度 INTERPOLATION_METHOD 'cubic' 插值方法 如果您使用VASPKIT，请记得引用哦！ V. Wang, N. Xu, J.-C. Liu, G. Tang, W.-T. Geng, VASPKIT: A User-Friendly Interface Facilitating High-Throughput Computing and Analysis Using VASP Code, Computer Physics Communications 267, 1080…

杂化泛函计算能带
type: item
date: 2021-12-01T17:50:00+08:00
description: 杂化泛函相比于DFT方法，在计算带隙方面更加准确，但是HSE06的杂化泛函需要KPOINTS里既有权重不为0的K点进行自洽计算，又要求有权重为0的高对称点计算能带性质。因此操作流程颇为繁琐。 第一步：准备KPATH.in文件，KPATH.in格式与使用PBE计算计算能带的格式完全相同，即为line-mode格式，可使用VASPKIT 303 (体相)或者302（二维）命令产生，也可以自定义生成，例如对于FCC结构，其推荐能带路径如下所如： KPATH.in文件内容如下： Generated by VASPKIT based on Hinuma et al.'s Paper, Comp. Mat. Sci. 128, 140 (2017), DOI: 10.1016/j.commatsci.2016.10.015. 10 Line-Mode Reciprocal 0.0000000000 0.0000000000 0.0000000000 GAMMA 0.5000000000 0.0000000000 0.5000000000 X 0.5000000000 0.0000000000 0.5000000000 X 0.6250000000 0.2500000000 0.6250000000 U 0.3750000000 0.3750000000 0.7500000000 K 0.0000000000 0.0000000000 0.0000000000 GAMMA 0.0000000000 0.0000000000 0.0000000000 GAMMA 0.5000000000 0.5000000000 0.5000000000 L 0.5000000000 0.5000000000 0.5000000000 L 0.5000000000 0.2500000000 0.7500000000 W 0.5000000000 0.2500000000 0.7500000000 W 0.5000000000 0.0000000000 0.5000000000 X 第二步：调用VASPKT-251命令产生用于杂化密度计算的KPOINTS文件。具体操作如下：重启vaspkit，输入25选择功能Hybrid-DFT Band-Structure，在下一个界面输入251选择Generate KPOINTS File for Hybrid Band-Structure Calculation。再输入1选择Monkhorst-Pack Scheme用MP方法生成自洽用的K点网格并根据建议输入0.04选择较密的K点密度（权重不为0的K点用于自恰计算），接下来还需手动指定能带路径上K点的密度，用于能带计算，再次输入0.04，即可生成HSE06杂化泛函所需的KPOINTS。VASPKIT最新版支持根据给定k点间隔自动确定不同能带路径上的K点数，从而保证在整个能带计算中均匀撒点。 ======================= K-Mesh Scheme ========================== 1) Monkhorst-Pack Scheme 2) Gamma Scheme 0) Quit 9) Back ------------->> 1 +-------------------------- Warm Tips --------------------------+ Input Kmesh-Resolution Value for SCF Calculation: (Typical Value: 0.02-0.04 is Generally Precise Enough) ------------>> 0.04 Input Kmesh-Resolution Value along K-Path for Band Calculation: (Typical Value: 0.03-0.05 for DFT and 0.04-0.06 for hybrid DFT) ------------>> 0.04 +---------------------------------------------------------------+ -->> (03) Reading K-Path From KPATH.in File... +-------------------------- Summary ----------------------------+ K-Mesh for SCF Calculation: 8 8 8 The Number of K-Points along K-Path No.1: 28 The Number of K-P…

DFT能带计算
type: item
date: 2021-12-01T17:16:00+08:00
description: 能带计算的KPOINTS与普通计算的KPOINTS不一样，通常需要第一布里渊区内的一条或几条高对称点路径来计算能带性质。传统的做法是通过SeeK-Path网站或者Material Studio软件获得晶体倒易空间第一布里渊区内的高对称点，再通过脚本插值生成高对称点路径上的K点，得到满足要求的KPOINTS。好消息是新版的vaspkit集成了与SeeK-path一致的算法分析晶体的高对称点，可以方便地生成PBE泛函和HSE06杂化泛函所需的KPOINTS。 在vaspkit/examples/hybrid_DFT_band目录下有一个使用杂化泛函计算磷化镓的能带结构的例子。同样也可以使用DFT计算该磷化镓结构的能带，只是传统的DFT泛函会低估带隙。为了计算能带，首先得获得晶体的第一布里渊区内的一条或几条高对称点路径。在有POSCAR的目录下运行vaspkit,输入3选择功能K-Path for Band-Structure，在下一个界面输入3选择Bulk Structure，你会得到以下信息： +-------------------------- Warm Tips --------------------------+ See An Example in vaspkit/examples/seek_kpath. This Feature Is Experimental & Check Your System using SeeK-Path. For More details See [www.materialscloud.org/work/tools/seekpath]. +---------------------------------------------------------------+ -->> (1) Reading Structural Parameters from POSCAR File... +-------------------------- Summary ----------------------------+ Prototype: AB Total Atoms in Input Cell: 2 Lattice Constants in Input Cell: 3.854 3.854 3.854 Lattice Angles in Input Cell: 60.000 60.000 60.000 Total Atoms in Primitive Cell: 2 Lattice Constants in Primitive Cell: 3.854 3.854 3.854 Lattice Angles in Primitive Cell: 60.000 60.000 60.000 Crystal System: Cubic Crystal Class: -43m Bravais Lattice: cF Extended Bravais Lattice: cF2 Space Group: 216 Point Group: 31 [ Td ] International: F-43m Symmetry Operations: 24 Suggested K-Path: (shown in the next line) [ GAMMA-X-U|K-GAMMA-L-W-X ] +---------------------------------------------------------------+ -->> (2) Written PRIMCELL.vasp file. -->> (3) Written KPATH.in File for Band-Structure Calculation. -->> (4) Written HIGH_SYMMETRY_POINTS File for Reference. -->> (5) Written POTCAR File with the Recommended Potential! +---------------------------------------------------------------+ | * DISCLAIMER * | | CHECK Your Results for Consistency if Necessary | | Bug Reports and Suggestions for Improvements Are Welcome | | Citation of VASPKIT Is Not Mandatory BUT Would Be Appreciated | | (^.^) GOOD LUCK (^.^) |…