Inpgen -- the FLEUR input generator » bulk and thin film inpgen differences

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#1 | bulk and thin film inpgen differences datum

Wed Apr 29, 2026 1:24 am

Hello,

I have this input file for the bulk material:

Mn3Ge

&input film=f cartesian=f /

1.0 0.0 0.0
-0.5 sqrt(3.0)/2.0 0.0
0.0 0.0 1.0
9.6402026110092500
1.0 1.0 0.8076

8
32 0.6666666667 0.3333333333 0.7500000000
32 0.3333333333 0.6666666667 0.2500000000
25 0.1632000000 0.3264000000 0.7500000000 Pi/2.0 Pi/2.0
25 0.6736000000 0.8368000000 0.7500000000 11.0*Pi/6.0 Pi/2.0
25 0.1632000000 0.8368000000 0.7500000000 7.0*Pi/6.0 Pi/2.0
25 0.8368000000 0.6736000000 0.2500000000 Pi/2.0 Pi/2.0
25 0.3264000000 0.1632000000 0.2500000000 11.0*Pi/6.0 Pi/2.0
25 0.8368000000 0.1632000000 0.2500000000 7.0*Pi/6.0 Pi/2.0

&kpt div1=24 div2=24 div3=24 gamma=t /

and this for a thin film containing one unit cell:

Mn3Ge (1-unit-cell thin film)

&input film=t cartesian=f /

1.0 0.0 0.0
-0.5 sqrt(3.0)/2.0 0.0
0.0 0.0 1.0
9.6402026110092500
1.0 1.0 0.8076

8
32 0.6666666667 0.3333333333 1.9463569071627670
32 0.3333333333 0.6666666667 -1.9463569071627670
25 0.1632000000 0.3264000000 1.9463569071627670 Pi/2.0 Pi/2.0
25 0.6736000000 0.8368000000 1.9463569071627670 11.0*Pi/6.0 Pi/2.0
25 0.1632000000 0.8368000000 1.9463569071627670 7.0*Pi/6.0 Pi/2.0
25 0.8368000000 0.6736000000 -1.9463569071627670 Pi/2.0 Pi/2.0
25 0.3264000000 0.1632000000 -1.9463569071627670 11.0*Pi/6.0 Pi/2.0
25 0.8368000000 0.1632000000 -1.9463569071627670 7.0*Pi/6.0 Pi/2.0

&kpt div1=24 div2=24 div3=1 gamma=t //

inpgening the bulk and the thin film files results in different Kmax, Gmax, GmaxXC and MT radii (see attached files) for the respective .xml files.
Why is this happening?

mgeo06 has attached files to this post

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#2 | RE: bulk and thin film inpgen differences datum

Thu Apr 30, 2026 6:35 pm

Gregor

Show info

Posts:	224
Registered since:	04.07.2021

This is kind of an extreme outcome of slight differences in the determination of the default parameters for film and for bulk calculations:

In the film case we make the MT radii slightly smaller, because of the practical experience with have with these setups. This has the consequence that the lmax parameters might also be smaller. In your case in the film calculation for Germanium you get an lmax of 8, while it is 10 in the bulk calculation. The kmax is then determined with:

1
 
input%rkmax = MAXVAL(atoms%lmax/atoms%rmt)

with some subsequent rounding.

So, nothing in the structure is wrong. You just get different defaults for the two cases.

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same lattice, different inp.xml files? �