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/)

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