Understood. I shall try this method as well and see how the results turn
out.


Thank you

On Tue, 7 Sept 2021 at 01:31, Nick Papior <[email protected]> wrote:

> Hi,
>
> The kgrid_Monkhorst_Pack block is in units of reciprocal lattice vectors.
> Secondly the displacement should only be used along periodic directions.
> Here you seem to have just added them for no particular reason.
>
> I think your block should look like this instead:
> %block kgrid.MonkhorstPack
>  1 0 0 0.
>  0 1 0 0.
>  0 0 32 0.5
> %endblock
> Please try and understand the difference between my block and what you had?
>
> Den ons. 1. sep. 2021 kl. 22.02 skrev Pasan Henadeera <
> [email protected]>:
>
>> Dear sir,
>> As per my understanding, the reciprocal lattice vectors (A,B,C) in 3D are
>> defined as
>> A=(2pi bxc)/(a (bxc))
>> where, a,b,c represent real space vectors with x marking cross product.
>>
>> Hence for a set of a,b,c vectors perpendicular to each other in the
>> positive real space, the reciprocal lattice vector A would fall along the
>> same direction as the real space vector a.
>>
>> If so, the specification of my k points for the band structure
>> calculation lie along the first lattice direction whereas my requirement is
>> in the third dimension (completely my fault).
>>
>> However, I do not understand your statement that my s*election of k
>> points are along a diagonal line of the 1st and 3rd lattice vectors*.
>> Can you please clarify regarding this and help me understand the fault.
>>
>>
>> Thank you
>>
>>
>> On Tue, 31 Aug 2021 at 06:39, Pasan Henadeera <[email protected]>
>> wrote:
>>
>>> Hi, thank you for the reply.
>>> 1. I tried with and without fractional coordinates and the results were
>>> similar.
>>> 2. The atomic mass was specified because I wanted to make sure that the
>>> problem was not caused due to that.
>>> 3. Yes, the k points could be a source of the problem.
>>> 4. I tried both SZ and DZ and there was not much variation in the
>>> results. I shall try using SZP and DZP as well.
>>>
>>> I shall work on your suggestions and let you know what happens. Thanks
>>> for the assistance.
>>>
>>>
>>> Thank you
>>>
>>> On Tue, 31 Aug 2021 at 01:30, Nick Papior <[email protected]> wrote:
>>>
>>>> Hi,
>>>>
>>>> A couple of notes on the input. Why are you using fractional
>>>> coordinates for such a system, it seems a bit weird to me. But ok, the
>>>> system looks ok.
>>>>
>>>> You don't need to use the AtomicMass block in case you want to use the
>>>> default mass of Si (which if I recall is 28.09).
>>>>
>>>> Your k-point input indicates to me that you don't understand what it
>>>> does? The k-points you have selected are along a diagonal line of the 1st
>>>> and 3rd lattice vector. You probably only want along the 3rd? Please
>>>> carefully go through your input options and what they mean.
>>>>
>>>> Lastly, did you try and converge the basis set? Using only SZ might not
>>>> be good enough here.
>>>>
>>>> Den søn. 29. aug. 2021 kl. 22.00 skrev Pasan Henadeera <
>>>> [email protected]>:
>>>>
>>>>> Hello Siesta users,
>>>>> I am trying to evaluate the band gap variation in Si nanowires
>>>>> (without any passivation). However, I have been unable to obtain a
>>>>> reasonable band structure comparable to available literature (
>>>>> https://doi.org/10.1016/j.physe.2005.12.094).
>>>>>
>>>>> Any ideas or suggestions?
>>>>>
>>>>>
>>>>> SystemName      Si
>>>>> SystemLabel     Si
>>>>>
>>>>> NumberOfSpecies         1
>>>>> NumberOfAtoms           57
>>>>>
>>>>> %block ChemicalSpeciesLabel
>>>>>   1  14  Si
>>>>> %endblock ChemicalSpeciesLabel
>>>>>
>>>>> %block AtomicMass
>>>>>   1  28
>>>>> %endblock AtomicMass
>>>>>
>>>>> LatticeConstant 5.3162811000 Ang
>>>>>
>>>>> %block LatticeVectors
>>>>>   0.0000000000 17.0000000000 0.0000000000
>>>>>   0.0000000000 0.0000000000 17.0000000000
>>>>>   1.0000000000 0.0000000000 0.0000000000
>>>>> %endblock LatticeVectors
>>>>>
>>>>>
>>>>> AtomicCoordinatesFormat Fractional
>>>>> %block AtomicCoordinatesAndAtomicSpecies
>>>>> 0.4218750001 0.4531250001 0.7500000009 1
>>>>> 0.4218750001 0.4843750001 0.2500000009 1
>>>>> 0.4208485475 0.5157487486 0.7512270222 1
>>>>> 0.4205211402 0.5462557586 0.2323127590 1
>>>>> 0.4842479144 0.4208701616 0.2481823356 1
>>>>> 0.4537269539 0.4205721769 0.7671556118 1
>>>>> 0.4386097200 0.4385553039 0.9829884767 1
>>>>> 0.4689609805 0.4376984553 0.5053350471 1
>>>>> 0.4688488746 0.4688446650 0.0003473838 1
>>>>> 0.4381741853 0.4690624505 0.5037780301 1
>>>>> 0.4533432439 0.4532006119 0.2542710091 1
>>>>> 0.4844977098 0.4534676431 0.7520747802 1
>>>>> 0.4843956661 0.4844028848 0.2508846043 1
>>>>> 0.4535760099 0.4845509954 0.7526387478 1
>>>>> 0.4379725900 0.5001831894 0.9964957459 1
>>>>> 0.4689187754 0.5000018849 0.4997524134 1
>>>>> 0.4688466704 0.5311626528 0.9994608317 1
>>>>> 0.4376911579 0.5310443690 0.4943530582 1
>>>>> 0.4535076989 0.5155265650 0.2484398088 1
>>>>> 0.4843981130 0.5156022583 0.7489904851 1
>>>>> 0.4845031869 0.5465300316 0.2479006330 1
>>>>> 0.4532537185 0.5467402717 0.7445710047 1
>>>>> 0.4386536374 0.5613490668 0.0209871088 1
>>>>> 0.4689504767 0.5623096662 0.4943742384 1
>>>>> 0.4537407911 0.5794778627 0.2321660756 1
>>>>> 0.4842634606 0.5791191600 0.7515145823 1
>>>>> 0.5462628443 0.4205258128 0.2322107930 1
>>>>> 0.5157447994 0.4208750213 0.7517376987 1
>>>>> 0.4999969254 0.4377903480 0.9998958351 1
>>>>> 0.5310470849 0.4376968379 0.4943589947 1
>>>>> 0.5311609069 0.4688409117 0.9995670075 1
>>>>> 0.4999982405 0.4689091066 0.4999235161 1
>>>>> 0.5154961788 0.4534701711 0.2478658343 1
>>>>> 0.5467429914 0.4532536631 0.7446390767 1
>>>>> 0.5465316338 0.4845048549 0.2478709280 1
>>>>> 0.5155991333 0.4843974423 0.7490231357 1
>>>>> 0.5000012391 0.5000012294 0.9999860448 1
>>>>> 0.5310933384 0.5000012038 0.4999818520 1
>>>>> 0.5311584743 0.5311590261 0.0003877805 1
>>>>> 0.5000006752 0.5310898094 0.4999793991 1
>>>>> 0.5155993795 0.5156016028 0.2509924240 1
>>>>> 0.5465322721 0.5154974225 0.7521165594 1
>>>>> 0.5467453831 0.5467413239 0.2554397791 1
>>>>> 0.5154934165 0.5465280455 0.7521133862 1
>>>>> 0.5000025233 0.5622200175 0.9999154108 1
>>>>> 0.5310541581 0.5623080249 0.5055918525 1
>>>>> 0.5157243943 0.5791157145 0.2486224609 1
>>>>> 0.5462587742 0.5794774930 0.7678772422 1
>>>>> 0.5613462417 0.4386515218 0.0210208787 1
>>>>> 0.5623109375 0.4689459928 0.4943827650 1
>>>>> 0.5794716486 0.4537426560 0.2321699186 1
>>>>> 0.5791173816 0.4842648445 0.7515189669 1
>>>>> 0.5622181911 0.5000006977 0.0000456673 1
>>>>> 0.5623061750 0.5310497879 0.5056290910 1
>>>>> 0.5791238231 0.5157378818 0.2484404107 1
>>>>> 0.5794790635 0.5462573038 0.7678478138 1
>>>>> 0.5613422586 0.5613429826 0.9788443617 1
>>>>> %endblock AtomicCoordinatesAndAtomicSpecies
>>>>>
>>>>> %block kgrid_Monkhorst_Pack
>>>>>    0   1   0   0.5
>>>>>    0   0   1   0.5
>>>>>    32  0   0   0.5
>>>>> %endblock kgrid_Monkhorst_Pack
>>>>>
>>>>> XC.functional           LDA
>>>>> XC.authors              CA
>>>>> SpinPolarized           .false.
>>>>> MeshCutoff              300 Ry
>>>>> kgrid_cutoff            100.0 Ang
>>>>>
>>>>> PAO.BasisSize   SZ
>>>>>
>>>>> MD.TypeOfRun       CG
>>>>> MD.VariableCell    true
>>>>> MD.NumCGsteps      500
>>>>> MD.MaxCGDispl      0.1 Bohr
>>>>> MD.MaxForceTol     0.1 eV/Ang
>>>>> MD.MaxStressTol    0.001 eV/Ang**3
>>>>> %block GeometryConstraints
>>>>>    position   1   2
>>>>>    stress     4   5   6
>>>>> %endblock GeometryConstraints
>>>>>
>>>>> MD.UseSaveXV true
>>>>>
>>>>> MaxSCFIterations  500
>>>>> DM.MixingWeight   0.01
>>>>> DM.NumberPulay    3
>>>>> DM.Tolerance      1.d-3
>>>>> ElectronicTemperature 25 meV
>>>>> SolutionMethod   diagon
>>>>>
>>>>> BandLinesScale       pi/a
>>>>> %block BandLines
>>>>> 1  -0.590938025   0.0000000000 0.0000000000 Y # -Y
>>>>> 50  0.0000000000  0.0000000000   0.0000000000 \Gamma
>>>>> 50  0.590938025 -0.0000000000 -0.0000000000 Y
>>>>> %endblock BandLines
>>>>>
>>>>>
>>>>>
>>>>> Thank you
>>>>> --
>>>>> Best regards
>>>>> Pasan Henadeera
>>>>>
>>>>> --
>>>>> SIESTA is supported by the Spanish Research Agency (AEI) and by the
>>>>> European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
>>>>>
>>>>
>>>>
>>>> --
>>>> Kind regards Nick
>>>>
>>>> --
>>>> SIESTA is supported by the Spanish Research Agency (AEI) and by the
>>>> European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
>>>>
>>>
>>>
>>> --
>>> Best regards
>>> Pasan Henadeera
>>>
>>
>>
>> --
>> Best regards
>> Pasan Henadeera
>>
>> --
>> SIESTA is supported by the Spanish Research Agency (AEI) and by the
>> European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
>>
>
>
> --
> Kind regards Nick
>
> --
> SIESTA is supported by the Spanish Research Agency (AEI) and by the
> European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
>


-- 
Best regards
Pasan Henadeera
-- 
SIESTA is supported by the Spanish Research Agency (AEI) and by the European 
H2020 MaX Centre of Excellence (http://www.max-centre.eu/)

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