You've activated the advanced settings in-app guide. In this guide, you will learn how to tune more advanced settings of the workflows. Those settings include k-points, pseudopotentials and more.
Click on Step 1: Select structure and follow the instructions to proceed.

Tasks

  1. Click on the From examples tab
  2. Click on Simple crystals
  3. Select Gold from the dropdown list
  4. Click the Confirm button to proceed

Tasks

  1. Select Structure as is (we skip the relaxation here)
  2. Open step 2.1 for further instructions

Tasks

  1. Check (activate) Electronic projected density of states (PDOS)
  2. Open step 2.2 for further instructions
Note: If running locally (for example, on the AiiDAlab demo server), we recommend selecting the fast protocol to reduce the computational cost.

Tasks

  1. Select the fast protocol
  2. In this guide, we will investigate in more detail the advanced settings that can be fine tuned. Open the Advanced settings panel for more instructions.
The advanced settings panel can be used to fine-tune the calculation parameters such as convergence thresholds, k-points, etc.

Possible tasks

This is just an outline of potential parameters that you could tune to see their impact. You do not need to change all of them. Feel free to check also those that we do not mention.
  1. Set the SCF Energy threshold to 1e-05 Ry/atom. You will realize that your calculation is much faster but it will not be properly converged.
    You could calculate the electronic structure and compare it to a calculation with stricter convergence criteria.
  2. When changing the k-points distance, see definition below, you immediately see the resulting k-mesh. Similar to the convergence threshold before, increasing the distance will impact the convergence of your calculation.
  3. In the Accuracy and precision section, you can select the pseudopotentials. We recommended the SSSP ones, a library of tested pseudo potentials maintained on the Materials Cloud (https://www.materialscloud.org/discover/sssp/table/efficiency). However, spin-orbit calculations require fully relativistic pseudopotentials. In this case, you could use the Pseudo-Dojo library (https://www.pseudo-dojo.org).
  4. You can choose between the PBE and PBEsol functional. You can switch between the two and do a structural relaxation and see the impact on the lattice constant.
  5. Finally, while SSSP and PseudoDojo already recommend converged plane-wave cutoffs, you can still change the cutoffs for the wavefunctions and the charge density in the Pseudopotentials subsection. Similar to the k-points above, this will affect computational cost and convergence.
  6. Open the PDOS tab for further examples.
Here you can set property specific settings.
  1. Similar to the k-points distance of the SCF calculation, you can also adjust the k-points distance of the NSCF calculation, which should be denser (i.e., smaller distance value).
  2. You can also tune the energy grid size for the PDOS and the broadening width.
  3. Click the Confirm button to proceed
Note that, depending on which advanced settings you changed, your calculations might become quite expensive. You do not need to submit the workflows, unless you want to. In this case, the guide ends here. If you do, be aware of the required simulation time!

In the submission step, we define the computational resources to be used in the calculations. The global resources are used to define resources across all workflow calculations. Optionally, you can override the resource settings for specific calculations.

Warning: If running locally (for example, on the AiiDAlab demo server), we recommend keeping nodes and CPUs at the default minimum of 1 each.

Once the resources are defined, we can optionally customize the workflow label (pre-filled according to the settings of steps 1 & 2), as well as provide a detailed description of the workflow. Once we are ready, we can submit the workflow. You first need to select which code (code executable + computer where this will run) to use for each step of the workflow. The Quantum ESPRESSO app should always install a local Quantum ESPRESSO executable that is sufficient for this tutorial, but you can setup additional codes installed on remote supercomputers. For more information on how to set up codes, please refer to the corresponding documentation.

Tasks

  1. Check that the the default options in the "Global resources" panel are the expected ones. Specifically: select 1 node and 1 CPU for each of the codes. Unless you want to run elsewhere, use the default codes on the AiiDAlab server (ending with `@localhost`) that are available from the dropdown menus.
  2. (Optional) customize the workflow label
  3. (Optional) add a workflow description
  4. Click the Submit button to proceed
Warning: The workflow may take a moment to submit.

Post-guide exercises

This guide does not contain any post-guide exercise. Feel free to go back into the Advanced settings tab and try some of the tasks suggested there!