Questions tagged [siesta]

For questions about using the SIESTA (Spanish Initiative for Electronic Simulations with Thousands of Atoms) electronic structure program.

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1answer
25 views

Tool to saturate the dangling bonds at the surface of nanostructures

When it comes to studying 2D, 1D or 0D nanomaterials, saturating the dangling bonds in the surface helps remove unwanted localized surface states from the band structure 1. However, so far I have not ...
7
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0answers
59 views

Geometry optimization using DFT

I have been attempting to optimize the structure of a Si nanowire using SIESTA. The original structure fed into the optimization is as follows. Once it is optimized, the structure would change to ...
6
votes
1answer
92 views

Generating a Gamma centered uniform k mesh in SIESTA DFT

The SIESTA DFT software provides to incorporate a Monkhorst-Pack k grid in DFT calculations. However to use the results with the BoltzTraP2 software, a Gamma centered k-grid with uniform distribution ...
7
votes
1answer
86 views

Evaluating Seebeck coefficient using DFT

I am working with semiconductor materials using the SIESTA DFT package. I have tried the BoltzTraP2 software interface with SIESTA, however the results (Seebeck coefficient of MgO and Si) did not ...
9
votes
3answers
74 views

Generating SIESTA FDF File from xyz or vasp?

I was using SIESTA, and just learning the program in general, however, was having trouble finding a suitable way to automatically generate FDF files, I understand this can be done manually, and have ...
8
votes
1answer
214 views

Can transmission spectrum value exceed 1 within bias window?

I'm trying to simulate a ZnO nanoribbon structure using TranSIESTA in the siesta package. When I performed the transport calculations, for a few bias points within the bias window, the transmission ...
4
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0answers
37 views

Nanowire Band Structure using Siesta DFT

I'm working with the Siesta DFT software, and managed to reproduce the band structure of bulk Si without any issues. However, when trying the same with a Si nanowire, the band structure looks nowhere ...
6
votes
1answer
66 views

How to make SCF converge in SIESTA?

I am trying to optimize some 4 atom Ni clusters. There are 4 types: one linear, one zigzag, one 2D and one 3D. Using the setup below, I don't get the calculations to converge even after 1000 SCF steps ...
9
votes
1answer
153 views

Quantum espresso vs SIESTA

I want to know which particular calculations are suitable for each of them. Is SIESTA free, as in can you work on it without license. (question is based on the fact for now that all these will be done ...
9
votes
1answer
282 views

Energy cut-off test meaning in atomic-like basis functions' DFT

I have been using SIESTA code to perform some practicals in my college and I have run energy cut-off tests before calculating properties of semi-conductors or insulator. As far as I am concerned, ...
11
votes
1answer
295 views

Why is Energy Cut-off and K-Point Convergence necessary in LCAO-based codes like SIESTA?

I am new to DFT-simulation and I wish to understand how it works behind the scene. As the title suggests I don't understand why LCAO-based codes have to define K-points and cut-off energies. I ...
10
votes
1answer
244 views

Increasing k-point grid to take DOS calculation

I was trying to compute some electronic properties for Pd using SIESTA and VASP for some computer practicals in my university, specially focused on band structure and density of states (DOS) using LDA ...
10
votes
1answer
218 views

How to calculate the band structure of a protein molecule

I want to calculate the band structure of a protein molecule. How can I do it using Siesta of Gaussian? I am thinking about QE/VASP as the number of atoms are 600 and computationally it is not ...
9
votes
1answer
94 views

Can I have a bond formed for only one spin?

I'm making a topological analysis of a nanotube interacting with some metals. The steps for the calculations were: Optimizing the geometry (I am using SIESTA code). Obtain the electronic density for ...
8
votes
2answers
122 views

Theories for electronic transport calculations

Both software I know that do electronic transport calculations (TranSIESTA and QuantumATK) , use Non-equilibrium Green's function (NEGF) method. Are there other theoretical methods that can be used to ...
9
votes
1answer
349 views

How is SIESTA and TranSIESTA different from plane wave DFT codes?

This question is complementary to a previous question. I have experience with the plane-wave DFT codes VASP and Quantum ESPRESSO. I would like to try SIESTA for the main purpose of using TranSIESTA ...
5
votes
1answer
99 views

Conductivity Computations of Molecular Wires [closed]

I am interested to compute the conductivity properties of some molecular organic wires in SIESTA. Since I am new in SIESTA, I would appreciate a guide for beginners to this field.
6
votes
1answer
476 views

How to calculate the photoluminescence spectrum from DFT band calculations?

Photoluminescence (PL) spectrum is one of the experimental observable used, among other things, to have an accurate idea about the material band structure. It can be calculated using the band ...
11
votes
2answers
898 views

How to calculate the effective mass from DFT band calculations?

One of the properties used in Solid State Physics, and specially in semiconductor physics, is the effective mass. It can be calculated from the energy dispersion relationship. The simple form, for ...
14
votes
3answers
272 views

Is there a (free) GUI to setup transport calculations using SIESTA?

I am very interested in doing transport calculation with SIESTA. My problem is that it is a little hard for me to understand and setup the input files to be used with TranSIESTA (the module that do ...