Yambo: An ab initio tool for excited state calculations

Abstract

yambo is an ab initio code for calculating quasiparticle energies and optical properties of electronic systems within the framework of many-body perturbation theory and time-dependent density functional theory. Quasiparticle energies are calculated within the GW approximation for the self-energy. Optical properties are evaluated either by solving the Bethe–Salpeter equation or by using the adiabatic local density approximation. yambo is a plane-wave code that, although particularly suited for calculations of periodic bulk systems, has been applied to a large variety of physical systems. yambo relies on efficient numerical techniques devised to treat systems with reduced dimensionality, or with a large number of degrees of freedom. The code has a user-friendly command-line based interface, flexible I/O procedures and is interfaced to several publicly available density functional ground-state codes. Program summary Program title: yambo Catalogue identifier: AEDH_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEDH_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence v2.0 No. of lines in distributed program, including test data, etc.: 149 265 No. of bytes in distributed program, including test data, etc.: 2 848 169 Distribution format: tar.gz Programming language: Fortran 95, C Computer: any computer architecture, running any flavor of UNIX Operating system: GNU/Linux, AIX, Irix, OS/X Has the code been vectorised or parallelized?: Yes RAM: 10–1000 Mbytes Classification: 7.3, 4.4, 7.2 External routines: • BLAS ( http://www.netlib.org/blas/) • LAPACK ( http://www.netlib.org/lapack/) • MPI ( http://www-unix.mcs.anl.gov/mpi/) is optional. • BLACS ( http://www.netlib.org/scalapack/) is optional. • SCALAPACK ( http://www.netlib.org/scalapack/) is optional. • FFTW ( http://www.fftw.org/) is optional. • netCDF ( http://www.unidata.ucar.edu/software/netcdf/) is optional. Nature of problem: Calculation of excited state properties (quasiparticles, excitons, plasmons) from first principles. Solution method: Many body perturbation theory (Dyson equation, Bethe Salpeter equation) and time-dependent density functional theory. Quasiparticle approximation. Plasmon-pole model for the dielectric screening. Plane wave basis set with norm conserving pseudopotentials. Unusual features: During execution, yambo supplies estimates of the elapsed and remaining time for completion of each runlevel. Very friendly shell-based user-interface. Additional comments: yambo was known as “SELF” prior to GPL release. It belongs to the suite of codes maintained and used by the European Theoretical Spectroscopy Facility (ETSF) [1]. Running time: The typical yambo running time can range from a few minutes to some days depending on the chosen level of approximation, and on the property and physical system under study.