About

EPW is an open-source F90/MPI/OpenMP/OpenACC software project for first-principles calculations of electron-phonon interactions and related materials properties. The code employs Density-functional perturbation theory and Maximally localized Wannier functions. The name is derived from the words “Electron-phonon Wannier” which refer to the Wannier-Fourier interpolation of the electron-phonon matrix elements employed by the code. The name of the code is “EPW” (not “Electron-phonon Wannier”). Since v5.3.1, the EPW project includes the ZG code for calculating electron-phonon couplings using supercells and the special displacement method, and the extension of this method to anharmonic systems.

The EPW project is led by its steering committee, which consists of Sabyasachi Tiwari, Samuel Poncé, Emmanouil Kioupakis, Roxana Margine, and Feliciano Giustino.

The most recent reference technical manuscript is:

  1. Lee, S. Poncé, K. Bushick, S. Hajinazar, J. Lafuente-Bartolome, J. Leveillee, C. Lian, J.-M. Lihm, F. Macheda, H. Mori, H. Paudyal, W. H. Sio, S. Tiwari, M. Zacharias, X. Zhang, N. Bonini, E. Kioupakis, E. R. Margine, and F. Giustino, Electron–phonon physics from first principles using the EPW code, npj Comput. Mater. 9, 156 (2023).

EPW is an independent code that participates in and is distributed with the Quantum ESPRESSO materials simulation suite, in collaboration with the Quantum ESPRESSO Foundation.

The EPW ecosystem also includes EPWpy, a Python framework and interoperability layer that automates EPW-based electron-phonon and many-body perturbation theory calculations, and handles the interfaces with BerkeleyGW and Abinit.

History

The first version of the code was written by Feliciano Giustino (EPW v1) while in the Cohen/Louie group at the University of California, Berkeley. Jesse Noffsinger performed the integration with Quantum ESPRESSO (EPW v2). Brad Malone and Cheol-Hwan Park contributed with tests and benchmarks to EPW v2. Roxana Margine implemented the anisotropic Eliashberg theory while in the Giustino group at the University of Oxford (EPW v3). Carla Verdi developed the electron-phonon interpolation for polar materials including Fröhlich correction while in the Giustino group at Oxford. Samuel Poncé made the code compatible with Quantum ESPRESSO v5, optimized it, and developed an automatic test farm for the code (EPW v4). Samuel Poncé implemented the electronic transport module while in the Giustino group at the University of Oxford (EPW v5). Hyungjun Lee coordinated code development in the Giustino group at the University of Texas at Austin (2019-2023). Emmanouil Kioupakis and Xiao Zhang contributed the indirect optical absoprtion module (EPW v5). Weng-Hong Sio, Chao Lian, and Jon Lafiente-Bartolomé developed the polaron module at Oxford and at UT Austin (EPW v5). Samuel Poncé introduced support for quadrupoles (EPW v5). Shashi Mishra and Hitoshi Mori (Binghamton U) developed the full-band Eliashberg module and the intermediate representation (EPW v5.9). Sabyasachi Tiwari developed the quasidegenerate perturbation theory module (EPW v5.8) and introduced image parallelism (EPW v6.0). Yiming Pan (Caruso group, Univerity of Kiel) implemented the time-dependent Boltzmann transort equations for ultrafast carrier dynamics (EPW v6.0). Wooil Yang introduced support for Hubbard-corrected DFPT+U (EPW v6.1). Tae Yun Kim (UT Austin) developed the GPU accelerated version of the code (EPW v6.1). Marios Zacharias developed the ZG code for special displacements (starting from EPW 5.3). Álvaro Carrasco-Álvarez (U Catholique Louvain) developed support for magnetic systems within the LSDA (EPW v6.1). Danylo Radevych and Aidan Thorn (Binghamton U) developed the EPW-VASP interoperability interface (EPW v6.1). Zhenbang Dai (UT Austin) developed the exciton-polaron module (EPW v6.1).

Sabyasachi Tiwari is the current project coordinator.

EPW is based on the method introduced in F. Giustino et al, Phys. Rev. B 76, 165108 (2007). An extended description of the most recent public release has been published in H. Lee al, npj Comput. Mater. 9, 156 (2023).

Substantive contributions

The following list records substantive contributions to EPW. Affiliations refer to the institution where the corresponding development was carried out.

Contributor(s)

Contribution

Release & Affiliation

Zhenbang Dai

Exciton-polaron module

UT Austin

Álvaro Carrasco-Álvarez

Support for LSDA

EPW v6.1; Louvain-la-Neuve

Danylo Radevych, Aidan Thorn

Interface with VASP

EPW v6.1; Binghamton U

Tae Yun Kim

GPU acceleration of EPW

EPW v6.1; UT Austin

Wooil Yang

Support for Hubbard-corrected DFPT+U calculations

EPW v6.1

Yiming Pan

Time-dependent Boltzmann equation for ultrafast dynamics

EPW v6.0, U Kiel

Shashi Mishra, Hitoshi Mori

Full-band Eliashberg & Intermediate representation

EPW v5.9; Bunghamton U

Sabyasachi Tiwari

Quasidegenerate perturbation theory and image parallelism

EPW v5.8 and v6.0; UT Austin

Marios Zacharias

ZG code and related tools for the special displacement method

EPW v5.3; Oxford / U Rennes / Cyprus Institute

Weng-Hong Sio, Chao Lian, Jon Lafuente-Bartolomé

First-principles polaron module

EPW v5; Oxford / UT Austin

Xiao Zhang

Indirect phonon-assisted optical absorption

EPW v5

Hyungjun Lee

Coordination of EPW development

UT Austin, 2019-2023

Samuel Poncé

Compatibility with Quantum ESPRESSO v5, code optimization, automated test farm, electronic transport, and support for quadrupoles

EPW v4-v5; Oxford / Louvain-la-Neuve

Carla Verdi

Long-range electron-phonon interpolation in polar materials

Oxford

Roxana Margine

Anisotropic Eliashberg theory

EPW v3; Oxford

Brad Malone, Cheol-Hwan Park

Tests and benchmarks

EPW v2; UC Berkeley

Jesse Noffsinger

Integration of EPW with Quantum ESPRESSO

EPW v2; UC Berkeley

Feliciano Giustino

Initial creation of EPW

EPW v1; UC Berkeley

The EPW Collaboration

As of April 2026, the EPW Collaboration includes (in alphabetic order):

Álvaro Carrasco-Álvarez, Kyle Bushick, Fabio Caruso, Jie-Cheng Chen, Zhenbang Dai, Adam Denchfield, Nina Girotto, Feliciano Giustino, Viet-Anh Ha, Sungyeb Jung, Emmanouil Kioupakis, Jon Lafuente-Bartolomé, Kaifa Luo, Tae Yun Kim, Jae-Mo Lihm, Zhe Liu, Roxana Margine, Hitoshi Mori, Yiming Pan, Samuel Poncé, Danylo Radevych, Young-Woo Son, Sabyasachi Tiwari, Shashi Mishra, Amanda Wang, Wooil Yang, Marios Zacharias, Xiao Zhang.

EPW is developed under git within the EPW GitLab portal.

As of March 2026, EPW consists of 104,251 lines of code (including comments).

What can be computed using EPW

EPW can be used to compute:

  • The total electron-phonon coupling strenght

  • The anisotropic Eliashberg spectral function

  • The transport spectral function

  • The anisotropic superconducting gap within the Eliashberg theory

  • The electron and phonon self-energies arising from the electron-phonon interaction

  • The phonon linewidths and lifetimes arising from the electron-phonon interaction

  • The electron linewidths and lifetimes arising from the electron-phonon interaction

  • The temperature-dependence of the carrier lifetimes

  • The spectral functions needed for the calculation of ARPES spectra

  • The temperature-dependent electron and hole mobility within the Boltzmann transport formalism

  • Magnetortransport coefficients such as the Hall mobility

  • Small and large polarons

  • Indirect phonon-assisted optical absorption

  • Temperature-dependent properties using the special displacement method

  • Direct plus indirect phonon-assisted absorption within quasidegenerate perturbation theory

  • Exciton polarons and self-trapped excitons