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#1 | Film calculation with oblique lattice datum

Tue Oct 22, 2024 5:24 pm

Tim

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Posts:	3
Registered since:	10.22.2024

Hello,
I'm trying to generate input for a supercell calculation in a hexagonal monolayer of Mn, but get an error from inpgen.
The supercell is created by repeating the unit cell three times into one direction.
Since the supercell lattice is oblique, I use a simple-monoclinic lattice for the setup.
The input for inpgen is:

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# three atom supercell of hexagonal Mn layer
&input film=t /
 
&lattice latsys='mP' a0=1.8897269 a=8.283 b=2.761 gamma=60 /
 
3
25.1  0.0  0.0  0.0
25.1  1.0  0.0  0.0
25.1  2.0  0.0  0.0
&factor 3.0 1.0 1.0 /
 
&atom id=25.1 rmt=2.40 jri=981 lmax=12 lnonsph=6 lo="3s 3p" /
&comp kmax=4.3 /
&exco xctyp='vwn' /
&kpt nkpt=1728 /
 

When invoking inpgen, I get the error message "film = t and z-axis not orthogonal", and the "out" file contains the following:

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vector 1 :   1.00000  0.00000  0.00000      length :   1.00000
vector 2 :   0.50000  0.86603  0.00000      length :   1.00000
vector 3 :   0.00000  0.00000  1.00000      length :   1.00000
angle between vectors (1,2) = 60.00000
angle between vectors (1,3) = 90.00000
angle between vectors (2,3) = 90.00000
   15.6526079127000        5.21753597090000        15.6526079127000       6.123233995736767E-017  6.123233995736767E-017  0.500000000000000     
 primitive       hexagonal   
 

 Point group of the Bravais lattice has  4 operations
 

 Point group of the Bravais lattice has  4 operations
 
 The system appears to be a supercell containing   3 primitive cells:
       1    0.000000    0.000000    0.000000
       2    0.333333    0.000000    0.000000
       3   -0.333333    0.000000    0.000000
 ***************ERROR***************
 film = t and z-axis not orthogonal
 ***************ERROR***************
 

I used the MaX-Release 7.2 of inpgen, but also tried MaX-Release 6.0, which threw a similar error.
I don't understand this output, the angles in lines 5 and 6 indicate that the z-axis is orthogonal to the film plane.

Best regards,
Tim Drevelow

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#2 | RE: Film calculation with oblique lattice datum

Tue Oct 29, 2024 5:05 pm

I suggest to directly supply the Bravais matrix to the input generator. Maybe that error message is always present for monoclinic lattices.

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#3 | RE: Film calculation with oblique lattice datum

Wed Oct 30, 2024 9:33 am

Tim

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Posts:	3
Registered since:	10.22.2024

Thank you for your reply.
I tried to follow your suggestion and supplied the Bravais matrix directly, with led to a new problem.
The input has been modified to

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# three atom supercell of hexagonal Mn layer
&input film=t cartesian=f /
     3.0   0.0    0.00
     0.5   0.5    0.00
     0.0   0.0    1.00
     5.2175359709
     1.0  -3.0    1.00
 
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25.1  0.0  0.0  0.0
25.1  1.0  0.0  0.0
25.1  2.0  0.0  0.0
&factor 3.0 1.0 1.0 /
 
&atom id=25.1 rmt=2.40 jri=981 lmax=12 lnonsph=6 lo="3s 3p" /
&comp kmax=4.3 /
&exco xctyp='vwn' /
&kpt nkpt=1728 /
 

When I invoke inpgen, I get the following output

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  Welcome to FLEUR - inpgen   ([I can't post links])   
      MaX-Release 7.2          ([I can't post links])
 Film calculation but no reasonable dVac provided
 Setting default for dVac
 Note:
 Default k point paths for film band structures
 are experimental. If the generated k point path
 is not correct please specify it directly.
 Processing k-point string: nk=1728                                 
 Generating a k-point set with         1728  k-points
          34         101        3434
 Processing k-point string: band=240                                
 Generating a k-point set for bandstructures with          240  k-points
 Note:
 Default k point paths for film band structures
 are experimental. If the generated k point path
 is not correct please specify it directly.
**************FLEUR-Error*****************
Error message: Not enough special points given and no default found
*****************************************
 

To me, it seems like inpgen has problems generating the default k-point path.
If so, is there a way to disable the generation of this path?

Best regards,
Tim

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#4 | RE: Film calculation with oblique lattice datum

Wed Oct 30, 2024 11:45 am (Last edited: Wed Oct 30, 2024 11:46 am)

Gregor

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Posts:	224
Registered since:	04.07.2021

Just add another line like

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&kpt nkpt=100 path='gamma=0,0,0;x=0.5,0.5,0.5' /

to your inpgen input to define another k-point set that is a path. If that is available the input generator will not try to generate a default path. If you add such a line you essentially define 2 kpoint sets in your inpgen input.

Of course, the naming of special points I chose in that path is random and not related to reality.

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Changing electron configuration � � thin film production by inp.xml, mismatch in z coordinates