By design SIESTA is very efficient for the description of finite systems as surfaces, adsorbates, nanotubes, nano-clusters, biological molecules, amorphous semiconductors, ferroelectric films, low-dimensional metals. This is one of the main advantage of SIESTA over plane-wave codes.
- Total and partial energies
- Atomic forces
- Stress tensor
- Electric dipole moment
- Macroscopic Polarisation
- Born Effective Charges
- Atomic, orbital and bond populations
- Electron density
- Charge analysis
- Magnetic moment
- Optical properties (imaginary part of the dielectric function)
- Local and orbital-projected density of states
- Band structure
- COOP and COHP curves for chemical bonding analysis
SIESTA allows the use of localised linear combinations of the occupied orbitals (valence-bond or Wannier-like functions), making the computer time and memory scale linearly with the number of atoms. Linear scaling algorithm enables simulations of tens of thousands atoms (>104) feasible using a modest workstation. Linear scaling O(N) works for systems with a finite HOMO-LUMO separation.
SIESTA’s efficiency stems from the use of strictly localized basis sets and from the implementation of linear-scaling algorithms, which can be applied to suitable systems. 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 strictly zero beyond a distance from the corresponding nucleus. Finite-support basis sets are the key for calculating the Hamiltonian and overlap matrices in O(N) operations.
SIESTA includes the TranSIESTA solver, which provides the ability to model open-boundary systems, where ballistic electron transport is taking place. TranSIESTA makes possible computing electronic transport properties, such as the zero-bias conductance and the I-V characteristic, of a nanoscale system in contact with two electrodes at different electrochemical potentials.
SIESTA is an open source code. Since the 13th of May 2016, with the 4.0 version announcement, SIESTA was released under the terms of the GPL open-source license. Source packages and access to the development versions can be obtained from the new development and distribution platform.
In 2015, SIMUNE established a strategic partnership with SIESTA offering support, training, and future development of the SIESTA code to facilitate materials design challenges. SIMUNE develops the project: SIESTA-PRO – Spanish Initiative for Electronic Simulations with Thousands of Atoms: Open Source code with professional support and warranty.