24小时热门版块排行榜

返回列表

当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖

lascqy

银虫 (小有名气)

应助: 3 (幼儿园)
金币: 239.7
帖子: 78
在线: 33.7小时
虫号: 804362

[交流] HSE能带计算中ISYM参数的问题

在用HSE计算能带的过程中，按照论坛里的K点设置方法，
band structures using hybrid functionals have to be calculated the following way:
-) First perform a selfconsistent Hartree-Fock/HSE calculation using a conventional KPOINTS file.
-) Copy the IBZKPT file to KPOINTS, and explicitely add all desired k-points along high-symmetry lines of the BZ that are needed for the bandstructure plot. Add the points at the end of the KPOINTS file, but set the weights of these added k-points to 0.
-) Do not forget to set the number of k-points in KPOINTS correctly (to the number of the k-points used in the standard mesh PLUS the number of the k-points along the lines), such that all k-points are used for the calculations.
-) NKRED can not be used.
-) Perform a second VASP run:
It is recommended to use the Davidson algorithm, since it converges that eigen energies at the new k-points fastest. Since VASP terminates when the total energy is converged to a certain threshold, it is important to force VASP to do a minimum number of steps, so that the orbitals at the new k-points are fully converged (note: since their weight is zero, they do not contribute to the total energy).
This can be done using e.g.

ALGO = N ; NELMIN = 5 ! Davidson, minimum 5 scf-steps
IBRION = 1 ! Use simple charge mixer, since
Pulay might blow up

-) The KS-eigenvalues of the states along the high-symmetry lines are written in OUTCAR, EIGENVAL, vasprun.xml; please cut the k-points required for the bandstructure from one of these files and proceed as usual (using p4vasp or any other graphics tool you usually use to produce bandstructure-plots)

Note: A Hartee-Fock calculation can NOT be continued from an existing CHGCAR file, since the non-local exchange is not determined by the charge density but by the density matrix and/or the KS-orbitals.

在ISYM=0或者2的时候貌似能带结构有很大区别，但在普通的GGA计算中没有这个现象，不知道这是不是我的个别现象呢，有没有人做过这个的来指点下？

回复此楼

» 抢金币啦！回帖就可以得到:

查看全部散金贴

1楼 2012-03-05 18:54:21

已阅回复此楼关注TA 给TA发消息送TA红花 TA的回帖

人生果

新虫 (小有名气)

应助: 0 (幼儿园)
金币: 0.1
帖子: 292
在线: 111.3小时
虫号: 1574493

★
小木虫: 金币+0.5, 给个红包，谢谢回帖

引用回帖:

5楼: Originally posted by lengqiang at 2012-11-24 14:21:33
版主，HSE计算能带时，ISYM需要怎样设置，0 or 2；计算DOS时，ISYM需要怎样设置那，谢谢。还有一个问题，我在用HSE时，加上NPAR=1，就报错，停止运算，有什么解决办法吗，谢谢

我在计算能带时 isym取0能得到很好的结果，DOS没没算过，请问你算过吗