1. Silicon: SCF, band structure & DOS

This is the “hello world” of LatticeMind. In one prompt you will compute the electronic ground state of bulk silicon, its band structure, and its density of states — and get plots and a report. It is the ideal first project.

What you need

LatticeMind installed with an API key (Connecting your AI model). To run the calculation you also need the RESCU solver and a license (Licenses and solver executables); without them you can still follow every step up to execution.

1.1. The prompt

Start LatticeMind (latticemind or latticemind-web) and type:

Do an SCF, band structure, and DOS calculation for silicon, and plot the
band structure and DOS.

That is the entire input. You do not specify the lattice constant, the k-point grid, the functional, or any RESCU keyword — LatticeMind fills those in.

1.2. What LatticeMind does

LatticeMind moves through its pipeline (How LatticeMind works) and reports each stage as it goes:

  1. Plans a three-step workflow: SCF → BAND-STRUCTURE → DOS, with both post-SCF steps depending on the converged SCF density.

  2. Builds the diamond-cubic silicon cell (two atoms, lattice constant 5.43 Å).

  3. Chooses parameters: the PBE (GGA) functional, a 12×12×12 k-point grid, and a double-zeta-polarized pseudopotential basis.

  4. Renders three input decks and wires the density hand-off from SCF to the band-structure and DOS steps.

  5. Validates the inputs and, when execution is enabled, runs them.

  6. Post-processes the outputs into plots and a report.

1.3. The generated SCF input

LatticeMind writes standard RESCU decks to project_root/inputs/. The SCF deck it produced for this project — which you can open, keep, and re-run — is:

info.calculationType = 'self-consistent';
info.savepath = './results/scf';
units.length = 'Angstrom';
domain.latvec = [...
    0.0 2.715 2.715;
    2.715 0.0 2.715;
    2.715 2.715 0.0;
];
domain.lowres = 0.5;
atom.fracxyz = [...
    0.0 0.0 0.0;
    0.25 0.25 0.25;
];
atom.element = [1 1];
element(1).species = 'Si';
element(1).path = './pseudopotentials/Si_PBE_TM_DZP.mat';
functional.libxc = true;
functional.list = {'XC_GGA_X_PBE' 'XC_GGA_C_PBE'};
kpoint.gridn = [12 12 12];
option.maxSCFiteration = 100;

Tip

Not happy with a choice? Just say so — “use an 8×8×8 k-grid” or “switch to LDA” — and LatticeMind re-plans and re-renders. You never edit the deck by hand (though you can).

1.4. Running it

Preview and launch:

/launch-preview     # see exactly what will run, and the cost
/execute on         # allow execution
run it

LatticeMind runs the SCF, feeds its density into the band-structure and DOS steps, and then post-processes the results.

1.5. The results

For this project LatticeMind extracted:

Quantity

Value

SCF total energy

−7.8827 Ha

Integrated electron count

8.000 e (exactly, an 8-electron cell)

Band gap (VBM → CBM)

0.585 eV

Note

PBE, like all semi-local functionals, underestimates the silicon band gap (experiment ≈ 1.1 eV). The ~0.6 eV result is the expected PBE value — a good sanity check, not an error. For an accurate gap you would use a hybrid functional; just ask LatticeMind for one.

The band structure and density of states are plotted automatically:

Silicon band structure computed with RESCU.

Fig. 1.5.1 Silicon band structure along the high-symmetry k-path, generated by LatticeMind from the one-line prompt.

Silicon density of states computed with RESCU.

Fig. 1.5.2 Silicon density of states. The Fermi level sits in the gap, as expected for a semiconductor.

1.6. Inspecting the project

Everything is on disk in the project folder (Projects & the workspace):

/outputs      # list results, plots, logs, and the report
/plots        # list generated plots
/analysis     # show extracted quantities (energy, gap, electron count)

The generated files include the RESCU decks (inputs/scf.input, band.input, dos.input), the raw output (results/scf.mat/.h5 and friends), the plots, and report.html.

1.7. What you learned

  • A single plain-language prompt produced a correct, multi-step DFT workflow.

  • LatticeMind chose the structure, functional, k-grid, and basis for you.

  • The density hand-off between SCF and its dependents was wired automatically.

  • You got validated inputs, real results, plots, and a report.

Next, try a spin-polarized metal in Ferromagnetic nickel: a two-step spin DOS, or an alloy in Building alloys & supercells (SiGe).