Engine 01 · establishedGPL
Quantum ESPRESSO
The open-source, peer-reviewed plane-wave pseudopotential suite most groups already cite. Choose it when you need continuity with published work or a reviewer expects it.
Engines & workflows
Two engines. Six workflows. One record.
Pick the engine that suits the system; Simatra keeps inputs, versions and outputs identical in shape either way.
Engine 02 · Simatra nativeGPL-3.0 · open source
KRONOS
Simatra's own plane-wave DFT engine, written from scratch in C++20 with CUDA, HIP and Metal backends, and validated against Quantum ESPRESSO for meV/atom precision.
The six workflows
| Workflow | Steps | You get |
|---|---|---|
| Quick DFT | vc-relax → scf → bands → dos | Band gap, Fermi level, DOS |
| Full DFT Analysis | relax → electronic → phonons → elastic | Complete characterisation and stability |
| Electronic Structure | scf → nscf → bands → dos | Band structure, DOS, gap |
| Phonon Analysis | scf → displacements → phonopy | Dispersion, phonon DOS, stability |
| Elastic Properties | strained cells → stress → fit | Cij, bulk and shear moduli, Born criteria |
| Structure Relaxation | vc-relax | Equilibrium positions and cell |
How Simatra’s simulations work
Simatra runs plane-wave Density Functional Theory (DFT) calculations on GPU-optimized cloud clusters (instance class GPU-Opt-V2). You choose between two computational engines:
Quantum ESPRESSO — an open-source, peer-reviewed plane-wave DFT code widely used across academic and industrial materials research. Simatra runs GPU-accelerated builds, and you can upload the pw.x input you already use on your university cluster: Simatra reads its structure, cutoffs and k-point grid.
KRONOS — Simatra’s own from-scratch, GPL-3.0-licensed plane-wave DFT engine (C++20, with CUDA/HIP/Metal GPU backends), validated against Quantum ESPRESSO for accuracy. See the KRONOS benchmarks for validation data and performance comparisons, or read our KRONOS vs Quantum ESPRESSO guide for help choosing between them.
Pre-configured workflows
Every calculation on Simatra starts from a workflow template, so you don’t hand-assemble multi-step runs:
- Quick DFT — structure relaxation plus electronic structure (bands + DOS); the fastest path to a band gap and Fermi-level check.
- Full DFT Analysis — complete characterization: structure optimization, electronic structure, phonons, mechanical properties, and stability analysis.
- Electronic Structure — band structure and density of states; identifies band gap, Fermi level, and electronic properties.
- Phonon Analysis — phonon dispersion and DOS; evaluates dynamical stability and thermal properties.
- Elastic Properties — elastic constants, bulk/shear modulus, and Born stability criteria.
- Structure Relaxation Only — optimize atomic positions and cell parameters.
Structures import as CIF, POSCAR or XSF files, or as a Quantum ESPRESSO pw.x input. Results come back as interactive reports — 3D charge densities, band structures, and relaxation trajectories you can explore in the browser and share with your lab — and every raw file stays downloadable: each step’s pw.x input and output, the SCF convergence history, the relaxation trajectory and the final structure. So a published result can be traced back to the exact workflow that produced it.
For the theory behind these workflows, start with our guides to DFT itself, convergence testing, and band structure calculations.
Citation
If you use results from Simatra in published work, please also cite Quantum ESPRESSO per their citation guidelines when your calculation used the QE engine.
Try it on your structure