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ElPhonInt

This page gives hints on how to compute the matrix elements of the electron-phonon interaction with the ABINIT package.

Introduction

The theory and details of the implementation are described in [Gonze2009] and [Gonze2016].

Basic calculations of electron-phonon interaction in ABINIT: one performs a normal ground state, then DFPT phonon calculations (using rfphon, with added keywords prepgkk and prtgkk, which saves the matrix elements to files suffixed GKK. The main change in this respect is that prtgkk now disables the use of symmetry in reducing q-points and perturbations. This avoids ambiguities in wave function phases due to band degeneracies. The resulting GKK files are merged using the mrggkk utility, and processed by anaddb.

With the implementation of phonons in PAW DFPT, the electron phonon coupling is also available in PAW, though this has not yet been tested extensively. The input variables for electron-phonon coupling in anaddb are described in [Gonze2009] and [Gonze2016].

Some details about the calculation of electron-phonon quantities in ABINIT and ANADDB can be found here.

Subsequently, the GKK file is used to compute many quantities, as explained in topic_PhononWidth, topic_TDepES and topic_ElPhonTransport.

A brand new ABINIT driver, focusing on the treatment of electron-phonon interaction is under heavy development. Most of the input variables for experts, with optdriver==7 are related to this development. It is operational as of v9.2, although the documentation is not yet fully upgraded.

compulsory:

basic:

useful:

  • dvdb_qcache_mb DVDB Q-CACHE size in Megabytes
  • eph_ahc_type Electron-PHonon: Allen-Heine-Cardona type
  • eph_frohl_ntheta Electron-PHonon: FROHLIich Number of THETA points
  • eph_frohlichm Electron-PHonon: FROHLICH Model
  • eph_ngqpt_fine Electron-PHonon: Number of Grid Q-PoinTs in FINE grid.
  • get1den GET the first-order density from _1DEN file
  • getdrhodb GET the DRHODB from…
  • getdvdb GET the DVDB from…
  • gkqwrite GKk for input Q grid to be WRITtEn to disk
  • ibte_niter Iterative Boltzmann Equation: max Number of ITERations
  • ibte_prep Iterative Boltzmann Equation PREPare
  • irdddb Integer that governs the ReaDing of DDB file
  • irddrhodb Integer that governs the ReaDing of DRHODB file
  • irddvdb Integer that governs the ReaDing of DVDB file
  • use_nonscf_gkk USE NON-SCF calculation of GKK matrix elements (electron phonon)

expert:

Selected Input Files

v5:

v7:

Tutorials