Tutorials

If you are starting out with Yambo, or even an experienced user, we recommend that you complete the following tutorials before trying to use Yambo for your system.

The tutorials are meant to give some introductory background to the key concepts behind Yambo. Practical topics such as convergence are also discussed. Nonetheless, users are invited to first read and study the background material in order to get familiar with the fundamental physical quantities.

Two kinds of tutorials are provided: stand-alone and modular.

Tutorial files

The tutorial CORE databases can be obtained

• from the Yambo Virtual Machine
• from the Yambo web-page
• from the Yambo GIT tutorial repository

From the Yambo Virtual Machine (VM)

If you are using the VM, a recent version of the tutorial files is provided.Follow these instructions to update the tutorial files to the most recent version.

From the Yambo website

If you are using your own installation or the docker, the files needed to run the tutorials can be downloaded from the lists below.

After downloading the tar.gz files just unpack them in the YAMBO_TUTORIALS folder. For example

$ mkdir YAMBO_TUTORIALS
$ mv hBN.tar.gz YAMBO_TUTORIALS
$ cd YAMBO_TUTORIALS
$ tar -xvfz hBN.tar.gz
$ ls YAMBO_TUTORIALS
  hBN

Files needed for modular tutorials

All of the following should be downloaded prior to following the modular tutorials:

Tutorial	File(s)
hBN	hBN.tar.gz
	hBN-convergence-kpoints.tar.gz
	hBN-2D.tar.gz
	hBN-2D-para.tar.gz

Files needed for stand-alone tutorials

At the start of each tutorial you will be told which specific file needs to be downloaded:

Tutorial	File(s)
Silicon	Silicon.tar.gz
	Silicon_Electron-Phonon.tar.gz
LiF	LiF.tar.gz
Aluminum	Aluminum.tar.gz
GaSb	GaSb.tar.gz
AlAs	AlAs.tar.gz
Hydrogen_Chain	Hydrogen_Chain.tar.gz

From the Git Tutorial Repository (advanced users)

If you are using your own installation or the docker, the tutorials repository contains the updated tutorials CORE databases. To use it

$ git clone https://github.com/yambo-code/tutorials.git YAMBO_TUTORIALS
$ cd YAMBO_TUTORIALS
$ ./setup.pl -install

Stand-alone tutorials

These tutorials are self-contained and cover a variety of mixed topics, both physical and methodological. They are designed to be followed from start to finish in one page and do not require previous knowledge of yambo. Each tutorial requires download of a specific core database, and typically they cover a specific physical system (like bulk GaSb or a hydrogen chain). Ground state input files and pseudopotentials are provided. Output files are also provided for reference.

These tutorials can be accessed directly from this page of from the side bar. They include different kind of subjects:

Warning: These tutorials were prepared using previous version of the Yambo code: some command lines, variables, reports and outputs can be slightly different from the last version of the code. Scripts for parsing output cannot work anymore and should be edited to work with the new outputs. New command lines can be accessed typing yambo -h

Basic

• Linear Response in 3D. Excitons at work
• GW convergence

Post Processing

• Yambo Post Processing (ypp)
• First Steps in YamboPy
• Yambopy tutorial: band structures
• Yambopy tutorial: Yambo databases

Advanced

• TDDFT Failure and long range correlations
• Linear response from real time simulations

GW and Quasi-particles

• Real Axis and Lifetimes
• Self-consistent GW on eigenvalues only

Electron phonon coupling

• Electron Phonon Coupling
• Optical properties at finite temperature
• Phonon-assisted luminescence by finite atomic displacements
• Exciton-phonon coupling and luminescence

Non linear response

• Linear response using Dynamical Berry phase
• Real time approach to non-linear response
• Correlation effects in the non-linear response
• Third Harmonic Generation
• Spin-orbit coupling and non-linear response
• Two-photon absorption
• Pump and Probe
• Parallelization for non-linear response calculations

Developing Yambo

• How to create a new project in Yambo
• How to create a new ypp interface
• Some hints on github

Modular tutorials

These tutorials are designed to provide a deeper understanding of specific yambo tasks and runlevels. They are designed to avoid repetition of common procedures and physical concepts. As such, they make use of the same physical systems: bulk hexagonal boron nitride hBN and a hBN sheet hBN-2D.

Warning: These tutorials were prepared using previous version of the Yambo code: some command lines, variables, reports and outputs can be slightly different from the last version of the code. Scripts for parsing output cannot work anymore and should be edited to work with the new outputs. New command lines can be accessed typing yambo -h

Introduction

• First steps: a walk through from DFT to optical properties

Quasiparticles in the GW approximation

• How to obtain the quasi-particle band structure of a bulk material: h-BN

Using Yambo in Parallel

This modules contains very general discussions of the parallel environment of Yambo. Still the actual run of the code is specific to the CECAM cluster. If you want to run these modules just replace the parallel queue instructions with simple MPI commands.

• Parallel GW (CECAM specific): strategies for running Yambo in parallel

GW_parallel_strategies_CECAM

• GW convergence (CECAM specific): use Yambo in parallel to converge a GW calculation for a layer of hBN (hBN-2D)

Excitons and the Bethe-Salpeter Equation

• Calculating optical spectra including excitonic effects: a step-by-step guide
• Obtaining a converged optical spectrum
• Many-body effects in low-dimensional systems: numerical issues and remedies
• Analysis of excitonic spectra in a 2D material

Yambopy

• First steps in Yambopy
• GW tutorial. Convergence and approximations (BN)
• Bethe-Salpeter equation tutorial. Optical absorption (BN)
• Database and plotting tutorial for quantum espresso: qepy
• Database and plotting tutorial for yambo: yambopy

Modules

Alternatively, users can learn more about a specific runlevel or task by looking at the individual documentation modules. These provide a focus on the input parameters, run time behaviour, and underlying physics. Although they can be followed separately, non-experts are urged to follow them as part of the more structured tutorials given above.