Announcements


almaBTE v1.1 released

posted Jun 21, 2017, 8:05 AM by Jesús Carrete Montaña

Version 1.1 of almaBTE has been released and is freely available from www.almabte.eu

AlmaBTE is a software package that solves the space- and time-dependent Boltzmann transport equation for phonons, using only ab-initio  calculated quantities as inputs. The software can currently model phonon transport in bulk crystals and alloys, thin films, superlattices, and multiscale structures with size features in the nm-μm range. Among other quantities, the program can output thermal conductances and effective thermal conductivities, space-resolved average temperature profiles, and heat-current distributions resolved in frequency and space.

In many respects, almaBTE is the successor of ShengBTE, building on its strengths and trying to extend the proven usefulness of ab-initio thermal conductivity calculations to new domains beyond single crystals in the stationary state. However, the design of almaBTE is more flexible, portable and efficient, as required by its far broader design goals.

A detailed description of the architecture of this new suite of tools and the underlying formalism can be found in this arXiv preprint.In addition to the programs described in the preprint, the almaBTE distribution contains a ShengBTE emulator specifically targeted at current ShengBTE users. This emulator is able to take unmodified ShentBTE inputs (the familiar CONTROL, FORCE_CONSTANTS_2ND and FORCE_CONSTANTS_3RD) and generate a set of outputs closely resembling those of ShengBTE. Although some of the less popular features of ShengBTE are not implemented in the emulator, for most users it will be more efficient than the original ShengBTE program. By way of example, running a thermal conductivity calculation with almaBTE for N different temperatures can be up to N times faster than with ShengBTE due to more efficient caching of temperature-independent quantities.

Another interesting development is the almaBTE database of force constants, with publication-quality sets of harmonic and anharmonic inputs for many semiconductors of theoretical and industrial interest.

We encourage ShengBTE users to try almaBTE and to contribute to its development.


ShengBTE v1.1.1 with support for spglib 1.9.*

posted Apr 3, 2017, 2:40 AM by Jesús Carrete Montaña   [ updated Apr 3, 2017, 2:46 AM ]

Version 1.1.0 of ShengBTE has been released and can be obtained from the Downloads section. Changes from v1.1.0 concern the C/Fortran interface, and allow users to compile ShengBTE with recent versions of the spglib library.

ShengBTE v1.1.0

posted May 11, 2016, 10:59 PM by Jesús Carrete Montaña

Version 1.1.0 of ShengBTE has been released and can be obtained from the Downloads section. New features include the ability to study several temperatures in the same run and compute weighted phase space volumes. A couple of issues with symmetrization have been fixed.

Due to the many changes to the output formats introduced by this new version, users are encouraged to read the documentation (in file README.md).

ShengBTE v1.0.2

posted Aug 2, 2015, 11:49 PM by Jesús Carrete Montaña

Version v1.0.2 can now be obtained from the Downloads section. This release improves the numerical stability of the non-analytic correction to the dynamical matrix and of the iterative solution to the BTE. It also ensures better compliance of the conductivity tensor with the symmetries of the system.

ShengBTE v1.0.1 and thirdorder.py v1.0.2

posted Apr 30, 2015, 2:19 AM by Jesús Carrete Montaña   [ updated Apr 30, 2015, 2:20 AM ]

ShengBTE v1.0.1 and thirdorder.py v1.0.2 are now available from the usual locations, including the Downloads section.

The new release of ShengBTE fixes a bug in the calculation of the projected density of states. With respect to thirdorder.py, the main changes are:
  • Some users of thirdorder.py on 64-bit platforms where sizeof(long)!=sizeof(int) reported a numpy error message complaining about a forbidden cast between int32 and int64. The issue should be solved now.
  • The default value of H (the size of the finite displacements) has been changed to 1e-3. Beware: this breaks backward compatibility, as calculations "sown" with 1.0.1 cannot be "reaped" with 1.0.2 without changing the value of H.
  • Some Cython optimizations have been re-enabled.

ShengBTE v1.0.0

posted Apr 7, 2015, 4:28 AM by Jesús Carrete Montaña   [ updated Apr 7, 2015, 4:29 AM ]

Version 1.0.0 of ShengBTE comes with a few new features:
  • Optimized code for handling RTA-only calculations when convergence=.false.
  • New code for avoiding very narrow peaks in the DOS and projected DOS. This has no effect on the thermal conductivity or other related quantities, but makes those densities easier to plot.
  • Implementation of time reversal symmetry (thanks go to Dr. Youdi Kuang).
v1.0.0 also fixes an important bug. Acoustic frequencies at Gamma were assumed to be exactly 0 in the scattering rate calculations, but not actually set to zero. This caused quite a lot of trouble for certain crystal structures.

Moreover, the documentation has been rewritten in Markdown to make it simpler to read from a text-only terminal.

The new release can be obtained from the Downloads section.

ShengBTE v0.9.16 and thirdorder.py v1.0.1

posted Mar 12, 2015, 9:44 AM by Jesús Carrete Montaña

ShengBTE v0.9.16 and thirdorder.py v1.0.1 are now available from the Downloads section.

v1.0.1 of thirdorder.py brings an overhaul of its core, now written in Cython. No Fortran compiler is needed to build the shared library now. Since BLAS used to be source of most linking problems, we hope that this change makes compilation easier. Please refer to README.md for details.

The main change in ShengBTE is the treatment of degenerate modes, whose group velocities are now properly symmetrized. Some new files have been added to the output.

As usual, some bugs have been ironed out here and there.

Quantum ESPRESSO support with ShengBTE v0.9.15 and thirdorder.py v1.0.0

posted Aug 20, 2014, 5:08 AM by Jesús Carrete Montaña   [ updated Aug 20, 2014, 5:09 AM ]

New releases of ShengBTE and thirdorder.py are available from the Downloads section. The new releases bring major changes in the form of support for Quantum ESPRESSO as a DFT backend, as well as some minor bug fixes in the code. These improvements have been made possible thanks to the coding and testing work of Dr. Antti J. Karttunen.

The changes affect the usage of thirdorder.py. Indeed, no script with the name "thirdorder.py" exists in this release. Code needed by both the ESPRESSO- and VASP-based workflows is now in the thirdorder_common module, the traditional VASP interface has been moved into thirdorder_vasp.py and the new ESPRESSO-based code is in thirdorder_espresso.py. Apart from the name of the script, no changes should be necessary in VASP-based workflows. Users interested in the new ESPRESSO interface should refer to the documentation.

We hope that that ESPRESSO support will serve to expand the user base of ShengBTE by providing the tools needed to complete a fully open-source workflow for atomistic calculations of the lattice thermal conductivity.

ShengBTE v0.9.14

posted Jul 6, 2014, 5:40 AM by Jesús Carrete Montaña   [ updated Jul 25, 2014, 3:34 AM by Wu Li ]

ShengBTE v0.9.14 brings many bug fixes (documentation, Grüneisen calculation...) and some new features:

- Compute emission and absorption contributions to phase space separately
- Output information about the full q-point mesh

We thank Dr. Albert Bartok-Partay from University of Cambridge for reporting the bug on Grüneisen calculation. 

ShengBTE article published

posted May 22, 2014, 10:27 AM by Jesús Carrete Montaña

Our article ShengBTE: A solver of the Boltzmann transport equation for phonons has been published as Computer Physics Communications 185 (2014) 1747-1758. Please see the How to cite section for bibliographical information.

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