Elk / News: Recent posts

Dear All,

Elk version 10.0.15 has just been released.

Most of the code is now considerably faster without incurring any loss of precision. This is thanks to more efficient use of the FFT as well as improved parallelism.

The phonon code has also been enhanced and now includes the non-analytic term in the dispersion which is calculated using the Born effective charges and the dielectric function. This gives the correct LO-TO splitting for polar semiconductors in the q → 0 limit. See the GaAs and hBC examples in the examples/phonons-superconductivity/ directory.... read more

Dear All,

Elk version 9.6.8 has just been released.

This version contains many optimisations, simplifications, additional documentation and examples.

Best wishes,
Kay Dewhurst, Sangeeta Sharma, Lars Nordström, Francesco Cricchio, Oscar Grånäs and Hardy Gross

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elk-9.6.8
-fixed an issue with Fermi surface plotting for the collinear spin-polarised case; the k-point set is not reduced for the collinear spin-polarised case; thanks to Wenhan Chen for discovering this
-many simplifications and optimisations in the code
-changed smallest allowed perturbation theory denominator (epsdev) from 0.005 to 0.0025 for DFPT phonon calculations
-added more examples, including the DFPT phonon dispersion of NiTe2 thanks to Jerry Li and the altermagnet CrSb thanks to Wenhan Chen
-added two more Wannier90 examples: graphene thanks to Jyoti Krishna and the spin Hall conductivity of Pt thanks to Markus Meinert
-further optimised OpenMP parallelism
-documented all the tasks in the manual

Dear All,

Elk version 9.5.14 has just been released. This contains further improvements to the Wannier90 interface.

Best wishes,
Kay Dewhurst, Sangeeta Sharma, Lars Nordström, Francesco Cricchio, Oscar Grånäs and Hardy Gross

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elk-9.5.14
-Wannier90 UNK files are now written; thanks to Andrew Shyichuk for the suggestion
-made a work-around for an Intel compiler bug which occurs when extra Wannier90 data is read from elk.in; this problem was discovered by Jerry Li
-added Wannier90 copper example thanks to Jerry Li
-improved the application of a constant electric field across the unit cell; the maximum distance over which it is applied can now be set with 'dmaxefc'
-included an example and test case for a constant electric field across the cell; the example can be found in elk/examples/electric-field/WSe2-bilayer and demonstrates band gap closure under applied high field strengths
-the average electric field in each muffin-tin is written to INFO.OUT when an electric field is applied
-added a high harmonic generation (HHG) example; see elk/examples/TDDFT-time-evolution/GaAs-HHG
-further improved OpenMP parallelism
-minor optimisations

Dear All,

Elk version 9.5.1 has just been released. This contains an important bug fix involving multi-threaded calling of FFTW. Thanks to Andreas Fischer for discovering this.

We also took the opportunity to improve the Wannier90 interface. See the examples in the elk/examples/Wannier90/ directory.

Best wishes,
Kay Dewhurst, Sangeeta Sharma, Lars Nordström, Francesco Cricchio, Oscar Grånäs and Hardy Gross... read more

Dear All,

Elk version 9.4.2 has just been released.

There are no significant new features in this version, just minor improvements and bug fixes.

Best wishes,
Kay Dewhurst, Sangeeta Sharma, Lars Nordström, Francesco Cricchio, Oscar Grånäs and Hardy Gross

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elk-9.4.2
-further improvements to the GW code, including changing some parts to single-precision arithmetic
-fixed a problem with thread allocation discovered by Andreas Fischer and colleagues
-replaced complex-complex FFTs to real-complex where possible
-task 485 now also outputs the frequency-dependent electric field as EFIELDW.OUT
-minor changes and optimisations

Dear All,

Elk version 9.1.15 has just been released.

New features include the piezoelectric and magnetoelectric tensors. This are calculated using the Berry phase method of R. D. King-Smith and David Vanderbilt, Phys. Rev. B 47, 1651(R) (1993). See the examples in the elk/examples/piezoelectric and elk/examples/magnetoelectric directories for details.

We've also updated the code to enable exchange-correlation functionals with Laplacian terms. This is useful some types of meta-GGAs, including those which are 'de-orbitalised' using the method of D. Mejia-Rodriguez and S. B. Trickey, Phys. Rev. B 98, 115161 (2018). Partial de-orbitalisation has also been improved and now works with the complete range of kinetic energy density functionals in Libxc; see arXiv:2304.02363.... read more

Dear All,

Elk version 8.8.26 has just been released.

This version features molecular dynamics using atomic trajectories determined from the Hellman-Feynman + IBS forces. See the examples in the elk/examples/molecular-dynamics directory for details. This technique can also be used as a simple structural prediction method using simulated annealing. Furthermore, the molecular dynamics forces can be subsequently used in a TDDFT Ehrenfest calculation, although this should be considered an experimental feature.... read more

Dear All,

Elk version 8.6.7 has just been released.

The newly-developed dynamical Born effective charges (dynBEC) are available in this version, see: Phys. Rev. B 106, L180303 (2022). However, these should be considered an experimental feature.

There are also several bug fixes as well as speed and memory efficiency improvements.

Note that the bundled BLAS/LAPACK and FFTPACK libraries have been removed. Elk should now be linked to external BLAS/LAPACK and FFT libraries. See the file 'make.inc' for instructions on how to do this.... read more

Dear All,

Elk version 8.4.6 has just been released.

This version has several important improvements and bug fixes, including a problem related to restarting TDDFT calculations (tasks 461 and 463). This was discovered by Antonio Sanna.

The second-order optics code has also been completely re-written and now follows the derivation and convention of Sipe and Ghahramani in Phys. Rev. B 48, 11705 (1993). Thanks go to Yunfan Liang and Xavier Gonze for pointing out an error in our non-linear optics paper Phys. Rev. B 67, 165332 (2003). This has now been fixed in the code.... read more

Dear All,

Elk version 8.3.15 has just been released.

This version is considerably faster than previous versions, particularly for spin-polarised calculations. This is thanks to improvements in the second-variational step as well as in computing the density and magnetisation. Calculation of potential matrix elements (used for example in TDDFT and ultra long-range) have been made single-precision. This speeds up the calculations by nearly a factor of 2 without any noticeable loss in overall precision.... read more

Dear All,

Elk version 7.2.42 has just been released.

The most significant improvement in this version is a new RAM disk feature for storing direct-access files in memory. This can be enabled with

ramdisk
.true.

Storing files in RAM instead of on disk can dramatically speed up certain calculations (such as TDDFT), particularly on computers with shared, parallel filesystems. Please let us know of any problems which arise from this as we will probably enable it by default in the next release. The status of the RAM disk can be written out after any calculation with task=68. Note that direct-access files are still written to disk as usual but data is subsequently read in from memory, thus all tasks can be run as before without fear of data loss.... read more

Dear All,

Elk version 7.1.14 has just been released.

This release improves the speed and memory footprint of the code, and is partly accomplished by switching some floating-point arithmetic in the second-variational step to single-precision.

We will continue this strategy to other parts of the code, in particular TDDFT and the ultra long-range method.

There are also bug fixes for the electron-phonon mean-field method. The spin density wave in bcc-Cr has been included as an example of the ultra long-range ansatz.... read more

Dear All,

Elk version 7.0.12 has just been released.

This release includes a new method coded by Chung-Yu Wang for including the electron-phonon interaction at the mean-field level.

Alyn James added an interface to the dynamical mean-field theory (DMFT) code TRIQS. For the moment this is a separate branch and can be downloaded here: https://github.com/AlynJ/Elk_interface-TRIQS

The ultra long-rage code has been further improved and the method has been published here: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.256402... read more

Dear All,

Elk version 6.8.4 has just been released.

Calculation of Born effective charges is now available using the method of R. D. King-Smith and David Vanderbilt, Phys. Rev. B 47, 1651(R) (1993). These work with most other features of the code.

Elk can now perform Ehrenfest dynamics during the TDDFT run. This works only for small atomic displacements and should be considered an experimental feature.... read more

Dear All,

Elk version 6.3.2 is now available for download.

The setup of the first-variational Hamiltonian and overlap matrices has been made considerably faster by rearranging loops and applying parallelism. Furthermore, integrals in the muffin-tins are now faster which should in turn speed up most tasks.

New features, including constant electric fields and arbitrary external potentials, have been added to the ultra long-range (ULR) part of the code. The ULR density, magnetisation, Kohn-Sham potential and magnetic field can now be plotted.... read more

Dear All,

Elk version 6.2.8 has just been released.

This release has been worked on for over a year and has many improvements, including:

1. A Wannier90 interface, thanks to Arsenii Gerasimov, Yaroslav Kvashnin and Lars Nordström and based on the original work of Duc Le and Jon Lafuente Bartolomé
2. Ultra long-range (ULR) calculations are now available thanks to Tristan Müller (an article describing this method is in preparation)
3. Self-consistent density GW is now possible thanks to Arkardy Davydov and others. This is a new method and works by updating the Kohn-Sham potential using the GW density.... read more

Dear All,

We are pleased to announce that the interface of Elk to Wannier90 has been completed.

This has been several years in the making and was programmed by Arsenii Gerasimov, Yaroslav Kvashnin and Lars Nordström; and based on the original work of Duc Le and Jon Lafuente Bartolomé.

A special fork of Elk version 5.2.14 with the interface is available on GitHub here: https://github.com/rohkeaID/elk-w90-improved... read more

Dear All,

Elk version 5.2.14 has just been released.

This fixes problems users were having with potential-only meta-GGA, MPI parallelism, meta-GGA forces and species generation. Thanks to Youzhao Lan, Michael Porer and Eike Schwier for discovering these.

We also took the opportunity to include code for the calculation of off-diagonal components of the dielectric function using TDDFT for q=0.

Finally, here is a last reminder of the Elk Workshop taking place at the Max Planck Institute of Microstructure Physics, Halle (Saale), Germany from 3 to 7 September, 2018. We only have two places left so if you would like to attend please send an email to Sangeeta Sharma (sharma@mpi-halle.mpg.de) before 30 June.... read more

Dear All,

Elk version 5.2.10 has just been released.

It's been over a year since the last release and Elk has been greatly improved in the meantime.

One of the main new features is the ability to produce ARPES-like GW band-structures (see the plot on the Elk website). This should work with most other features of the code, including non-collinear magnetism, but is computationally very expensive.

We've also added fully variational meta-GGA (in the generalised Kohn-Sham sense) using Libxc version 4. Previously, only potential-type meta-GGA functionals could be used.... read more

Dear All,

Elk version 4.3.6 has just been released.

The GW approximation is now available thanks to Arkadiy Davydov. It is a finite-temperature implementation and should work for insulators and metals, as well as non-collinear magnetism and spin-orbit coupling. This is still an experimental feature which can only output spectral functions on the real frequency axis. Nevertheless, we would appreciate any feedback from users trying this out. See the 'examples/GW' directory.... read more

Dear All,

Elk version 4.0.15 has just been released.

We have spent the last few months converting the muffin-tin functions to a packed format. This is in anticipation of adding long-range physics to our time-evolution code, as well as the GW-approximation.

As a consequence of this, the whole code should be noticeably faster and more memory efficient. It is also fully backward and forward compatible. Please let us know if you discover any unusual behaviour in this version -- a great many routines had to be modified.... read more

Dear All,

Elk version 3.3.15 has just been made available.

In this release we focused on improving perturbation theory phonon calculations. Electron-phonon coupling has also been updated and now makes reliable predictions of coupling constants which are in good agreement with other codes.

Lots of general improvements in speed and memory efficiency have also been made and the code should be noticeably faster for many tasks.... read more

Dear All,

Elk version 3.1.12 has just been released.

An inaccuracy in the scalar relativistic part of the code, which has existed for around 12 years, has been fixed. This may slightly affect calculations of heavy elements. Special thanks to Stefaan Cottenier, José A. Flores Livas and Marcin Dulak for the extensive calculations.

We further added to the TDDFT time-evolution part of the code. It is now possible to add constant and linearly increasing electric fields. In addition, the TDDFT code now works with DFT+U enabling the investigation of strongly correlated materials exposed to intense laser pulses.... read more

Dear All,

Elk version 3.0.4 has just been released.

The main new feature of this version is real-time evolution in solids. This has been the PhD work of Kevin Krieger for the past three years. It is very much an experimental feature and thus not suitable for production work just yet.

David Ernsting and Stephen Dugdale also added electron momentum density plots which may be compared to Compton profiles. This is also experimental and should not be used for production work.... read more

Dear All,

Elk version 2.3.22 has just been released.

New in this version are fixed tensor moment (FTM) calculations, see Phys. Rev. Lett. 103, 107202 (2009), coded by Francesco Cricchio, Lars and JKD. This is however an experimental feature and should not be used for production.

The code which makes the first-variational (FV) Hamiltonian real for systems with inversion symmetry has been restored in this version. In such cases, the FV calculation is faster by a factor of about four.... read more