# Tag for dipole correction in monolayers

**URL:** <https://discourse.abinit.org/t/tag-for-dipole-correction-in-monolayers/3806>\
**Category:** Ground state\
**Tags:** testing\
**Created:** [February 3, 2026, 8:23pm UTC](https://discourse.abinit.org/t/tag-for-dipole-correction-in-monolayers/3806 "2026-02-03T20:23:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Dom\_7](https://discourse.abinit.org/letter_avatar_proxy/v4/letter/d/7bcc69/32.png) [@Dom\_7](https://discourse.abinit.org/u/Dom_7)\
**Post date:** [February 3, 2026, 8:23pm UTC](https://discourse.abinit.org/t/tag-for-dipole-correction-in-monolayers/3806/1 "2026-02-03T20:23:44Z")

</div>

Hi everyone,

Is there a tag in ABINIT to account for the dipole corrections along the elongated axis in studying monolayers/2D materials?

I am looking to do something analogous to what VASP does with the tags LDIPOL, DIPOL, [https://www.vasp.at/wiki/index.php/LDIPOL](https://www.vasp.at/wiki/index.php/LDIPOL).

Thanks  
Dominic

---

<div class="post-metadata">

**Author:** ![Dom\_7](https://discourse.abinit.org/letter_avatar_proxy/v4/letter/d/7bcc69/32.png) [@Dom\_7](https://discourse.abinit.org/u/Dom_7)\
**Post date:** [February 11, 2026, 2:30am UTC](https://discourse.abinit.org/t/tag-for-dipole-correction-in-monolayers/3806/2 "2026-02-11T02:30:43Z")

</div>

Hi,

I constructed a symmetric slab for the SrTiO₃ case by building a large supercell elongated along the z-direction and placing the atoms in the center. The slab consists of a SrO–TiO₂–SrO stacking sequence, which should cancel the net dipole moment. Based on this symmetry, I believe explicit dipole corrections may not be necessary, but I wanted to confirm if this assumption is valid in ABINIT.

Additionally, I wanted to ask whether there are recommended tags or settings that should be included for reliable internal coordinate relaxations and subsequent phonon calculations for slab geometries.

In my current relaxation runs, the SCF convergence only reaches around 1×10⁻¹² in tolvrs even after ~350 steps. I am wondering whether this could be related to missing or suboptimal input parameters, particularly for vacuum/slab systems.

I would appreciate any suggestions or best practices for:  
• Dipole or electrostatic corrections in 2D slab systems  
• Recommended relaxation settings for slabs with vacuum  
• Any additional considerations before performing DFPT phonon calculations

```auto
ndtset 1 

# Optimization control
ionmov 2 
optcell 0 # Fixed cell (Required for vacuum calculations)
ntime 100      
tolmxf 1.0e-6   

ecutsm 0.5      
chkprim 0

# Cell parameters
acell 1.0358459799E+01 1.0358459799E+01 4.4196407571E+01 

rprim 1.0000000000E+00 0.0000000000E+00 0.0000000000E+00
         0.0000000000E+00 1.0000000000E+00 0.0000000000E+00
         0.0000000000E+00 0.0000000000E+00 1.0000000000E+00
        
natom 14     
ntypat 3   
typat 1 1 1 1 2 2 3 3 3 3 3 3 3 3   
znucl 38 22 8   

xred     
      0.0000000000E+00 5.0000000000E-01 4.1666666667E-01
      5.0000000000E-01 0.0000000000E+00 4.1666666667E-01
      5.0000000000E-01 0.0000000000E+00 5.8333333333E-01
      0.0000000000E+00 5.0000000000E-01 5.8333333333E-01
      5.0000000000E-01 5.0000000000E-01 5.0000000000E-01
      0.0000000000E+00 0.0000000000E+00 5.0000000000E-01
      7.7346871979E-01 2.7346871979E-01 5.0000000000E-01
      7.2653128021E-01 7.7346871979E-01 5.0000000000E-01
      2.7346871979E-01 2.2653128021E-01 5.0000000000E-01
      2.2653128021E-01 7.2653128021E-01 5.0000000000E-01
      5.0000000000E-01 5.0000000000E-01 4.1666666667E-01
      0.0000000000E+00 0.0000000000E+00 4.1666666667E-01
      0.0000000000E+00 0.0000000000E+00 5.8333333333E-01
      5.0000000000E-01 5.0000000000E-01 5.8333333333E-01

pp_dirpath "~/pseudo/PBEsol/"
pseudos "Sr.psp8, Ti.psp8, O.psp8"

ecut 30.0 
ngkpt 8 8 1 # 1 k-point in Z is sufficient for vacuum
kptopt 1
nshiftk 1
shiftk 0.0 0.0 0.0
nstep 500        
tolvrs 1.0d-12    
diemac 6.0

```

Thanks  
Dominic

 ![Screenshot from 2026-02-10 20-30-03](https://discourse.abinit.org/uploads/default/original/1X/d2fc65f7d8127318cc6ebdb8401ace58ea7753d0.png)