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

Make an empty folder, start LatticeMind in it (latticemind, or latticemind-web and choose the folder), 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 works through the request (How LatticeMind works), leaving one line per step on screen:

1. Sets up three calculations: SCF → BAND-STRUCTURE → DOS, with the band structure and DOS both reading 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. Writes and checks the three input files, pointing the band-structure and DOS inputs at the SCF density.

5. Asks your permission to run them, then runs them in order.

6. Reads the results, draws the figures and answers with the numbers.

1.3. The generated SCF input

LatticeMind writes standard RESCU input files at the top of the project folder. The SCF input 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 rewrites the inputs before asking to run them. You never have to edit the file by hand (though you can).

1.4. Running it

Before anything runs, LatticeMind shows what it will run, on which machine and in which folder, and asks:

1. yes   2. yes, always   3. no

Answer yes (or go ahead, run it). LatticeMind runs the SCF, feeds its density into the band-structure and DOS runs, and streams RESCU’s iteration log into the session while it works. To see the inputs first, ask “prepare the inputs but do not run anything” instead.

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:

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

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

1.6. Growing the project, turn by turn

You do not have to ask for everything up front. The same project could have started with just the SCF and band structure, and gained its DOS later:

can you add a dos calculation and plot the dos for the converged density

A follow-up reuses whatever is already converged in the folder — here, only the DOS actually runs, in well under a minute, and its plot lands beside the band structure. This is the intended way to work: each request builds on the last, completed steps are never recomputed, and a finished run never blocks its own project from continuing.

Fig. 1.6.1 The DOS added by the one-line continuation above, computed from the density the SCF step had already saved. The Fermi level sits in the gap.

1.7. Inspecting the project

Everything is on disk in the project folder (Projects & the workspace): the RESCU inputs at the top of the folder (scf.input, bs.input, dos.input), the raw output under results/ (.mat/.h5 and each run’s logs), and the figures under results/plots/. Ask in plain words for what you need — “what did the SCF converge to?”, “list the figures” — or use:

/status       # what exists, what is running, what is waiting
/report       # write the evidence report (HTML and Markdown) under results/

1.8. 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 approved one launch and got checked inputs, real results, plots, and a report on request.

Next, plot a III–V band structure in GaAs: band structure along the FCC path, run a k-point convergence study in Aluminium: a k-point convergence study, try a spin-polarized metal in Ferromagnetic nickel: a two-step spin DOS, or an alloy in Building alloys & supercells (SiGe).