SIESTA (computer program): Difference between revisions

Revision as of 11:29, 18 January 2018

Revision as of 11:36, 18 January 2018

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SIESTA main characteristics are:

* It uses the standard Kohn-Sham selfconsistent [[Density functional theory|density functiona]]<nowiki/>l method in the [[Local-density approximation|local density]] (LDA-LSD) and generalized gradient (GGA) approximations, as well as in a non local functional that includes [[van der Waals interactions]] (VDW-DF).

* It uses norm-conserving [[Pseudopotential|pseudopotentials]] in their fully nonlocal (Kleinman-Bylander) form.

* It uses [[Atomic orbital|atomic orbitals]] as a basis set, allowing unlimited multiple-zeta and angular momenta, polarization and off-site orbitals. The radial shape of every orbital is numerical and any shape can be used and provided by the user, with the only condition that it has to be of finite support, i.e., it has to be strictly zero beyond a user-provided distance from the corresponding nucleus. Finite-support basis sets are the key for calculating the Hamiltonian and overlap matrices in O(N) operations.

* Projects the electron wavefunctions and density onto a real-space grid in order to calculate the Hartree and exchange-correlation potentials and their matrix elements.

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* Variable cell dynamics (Parrinello-Rahman).

* [[Spin polarization|Spin polarized]] calculations (collinear or not).

* k-sampling of the [[Brillouin zone]].

* Local and orbital-projected [[density of states]].

* COOP and COHP curves for chemical bonding analysis.

* [[Dielectric polarization]].

* Vibrations (phonons).

* Band structure.

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== Strengths of SIESTA ==

SIESTA main strengths are:

SIESTA is an open source code with quality and functionalities comparable to or higher than other similar codes on the market. Its main strengths are:

# '''Flexible code''' in accuracy

# It can tackle '''computationally demanding systems'''  (systems currently out of the reach of plane-wave codes)

# '''High efficient''' parallelization

# '''Professional support and warranty''' (www.simune.eu)

The use of linear combination of numerical atomic orbitals makes SIESTA a flexible and efficient DFT code. SIESTA is able to produce very fast calculations with small basis sets, allowing computing systems with a thousand of atoms. At the same time, the use of more complete and accurate bases allows to achieve accuracies comparable to those of standard plane waves calculations, still at an advantageous computational cost.

== Implemented Solutions ==

* Collinear and non-collinear spin polarized calculations

* Efficient implementation of Van der Waals functional

* Wannier function implementation

* TranSIESTA/TBTrans module (NEW! In version 4.1)

* On-site Coulomb corrections (DFT+U) (NEW! In version 4.1)

* Description of strong localized electrons, transition metal oxides

* Spin-orbit coupling (SOC) (NEW! In version 4.1)

* Topological insulator, semiconductor structures, and quantum-transport calculations

* NEB (Nudged Elastic Band) (interfacing with [https://github.com/siesta-project/flos LUA]) (NEW! In version 4.1)

== Applications ==