You've activated the basic in-app guide. In this guide, you will learn how to use the app to build and submit a workflow of Quantum ESPRESSO calculations designed to compute the electronic structure of bulk gold. Click on Step 1: Select structure and follow the instructions to proceed.
In the structure selection step, we select a structure for the calculation in one of several ways: Once selected, we can view the structure in the viewer below. We can also edit the structure using the available structure editors. When done, we can choose to modify the structure label and/or provide a description. These will be attached to the input structure in your AiiDA database.

Tasks

In this first tutorial, we will compute use a gold structure, selecting it from the examples that we provide.
  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
Warning: If the confirmed structure is not yet stored in the AiiDA database, it will be stored automatically when you proceed to the next step.
Warning: Changes after confirmation will reset the following steps.
In this second step (Configure workflow), we define the workflow tasks, such as optimizing the structure geometry and/or computing certain properties. We also select in this step the parameters for the workflow calculations.

Tasks

  1. Select Full geometry relaxation
  2. Open step 2.1 for further instructions
Here we select the properties to calculate. Each property is associated with a workflow that will submit one or more calculations.

Tasks

  1. Check (activate) Electronic band structure
  2. Check (activate) Electronic projected density of states (PDOS)
  3. Open step 2.2 for further instructions
Here we can customize the calculation parameters. The settings are divided into several tabs. Two tabs are always present: Additionally, each plugin activated in the previous step 2.1 can add additional tabs. If we activated the two checkboxes in step 2.1, we should also see the two tabs "Band Structure" and "PDOS". Note that the app pre-configures defaults for most parameters.
See further instructions in the Basic settings panel below.
The basic settings panel provides top-level calculation settings including the electronic and magnetic properties of the material, and if spin-orbit coupling is to be considered. It also provides a choice of three protocols that pre-configure many calculation settings, balancing speed with precision.
Note: If running locally (for example, on the AiiDAlab demo server), we recommend selecting the fast protocol to reduce the computational cost and avoid crashes due to insufficient resources.

Tasks

  1. Select the Fast protocol
  2. (Optional) visit the Advanced settings panel (we will not customize them in this tutorial)
  3. Switch to the Band structure tab
Here we configure the settings for computing the band structure.

Tasks

  1. Check (activate) Fat bands calculation
  2. (Optional) visit the PDOS panel (we will not customize PDOS options in this tutorial)
  3. Click the Confirm button to proceed
Warning: Changes after confirmation will reset the following steps.

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.
Below you can monitor the status of the calculation, that might take several minutes to conclude even if we are using the fast protocol. A summary of calculation parameters is also provided. Raw input and output files may be downloaded upon workflow completion, as well as an AiiDA archive containing the full calculation provenance (that can be reimported by other AiiDAlab users and allows to reload the calculation).

Tasks

  1. If not already there, switch over to the Status panel
  2. In the process tree, follow (by clicking) Quantum ESPRESSO app workflow -> Structure relaxation workflow manager -> Structure relaxation workflow
  3. Click on Structure Geometry optimization (`pw.x`) to view the output of the calculation (if the calculation is still running, you will see a scrollable running log of its output)
    4. Note: You may see more than one structure relaxation workflows, with the first one(s) possibly marked with ❌. This is expected. Due to the fast protocol, convergence may not be reached in the first attempt, prompting the workflow to run a final relaxation step. The final step should be marked with a ✅.
  4. While the calculation is running, switch over to the Summary panel to view the submitted parameters
  5. When ready, switch over to the Results panel for further instructions
Here in the results panel, each tab will open results pertaining to a specific calculation submitted by the workflow.
See further instructions below in the "Structure" tab.
In the structure results panel, we can view the initial structure selected for the calculation. The panel is mostly the same as the one we saw in the structure selection step, with the notable additions of the structure node info and structure coordinates table. Most importantly, once structure relaxation is complete, the toggle button below the title will become active and allow us to switch between the initial and relaxed structure.

Tasks

  1. Once the calculation is complete, click on View relaxed to switch to view the relaxed structure
  2. Switch between the views, taking note of the differences in cell parameters (vector lengths/angles and volume) and atomic positions
  3. When ready, switch over to the Electronic bands + PDOS panel

Tasks

  1. Once the calculation is complete, click on the Load results button to load the available results
    2. Warning: It is possible to load results as soon as one of the two calculations is available. However, the following steps require both sets of data . Once both are available, make sure to check both bands and PDOS and click Apply selection.
  2. Several controls are at your disposal for adjusting the plot. For now, check the "Orbital grouping" options, but keep the default grouping by angular momentum
  3. Identify the Au-5d states (you can also double click on Au-5d in the legend to only show it and hide all other curves)
  4. If selected, deselect the Au-5d in the legend (double click until all states are reactivated)
  5. Double click on the plot to zoom out
  6. Identify the Au semicore states (drag to zoom; use the controls below the plot to change the color of a state, if two colors are too similar to distinguish between them)
  7. Feel free to zoom in and out and note how the DOS is synchronized with the band structure panel. Note that to zoom out, you can hover on the plot and use the little "Home" icon that appears on the top right of the plots (more tools are also available there). When ready, you can continue to the post-guide exercises at the bottom of the app

Post-guide exercises

  1. Switch back to the Summary panel of the results step
    • Download the workflow's raw data (zip file containing a folder hierarchy of the inputs and outputs)
      • Compare it against the process tree in the Status panel of the results step
      • Verify that they are the same by traversing both trees
    • (Advanced users) download the AiiDA archive
      • The archive includes the full calculation provenance and can be imported into any AiiDA instance
      • This reproduces the whole dataset on the receiving instance as if it was executed there
      • More details can be found here
  2. Use the app to compute the band structure of Si
    • See if you get a band gap (Important note: DFT is not expected to predict the correct gap!)
    • Verify that the valence bands are mostly of p character, while conduction bands are mostly of s character
  3. Explore the AiiDA database by viewing the calculation history
    • This will open a Jupyter notebook (new tab), where you can search, filter, and sort a table of all calculations stored in the AiiDA database
    • Find your recent calculations for Au (and Si if exercise 2 was submitted)
    • Click on the id of either calculation to open it in a new instance of the app (new tab)
    • Verify that it is indeed your previously submitted calculation, results included (if available)