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Usage

This guide covers common use cases for QE-to-TCAD.

Full workflow (PyPI)​

pip install 'qe-to-tcad[tcad]'

Then export your Materials Project key (see Installation), and run:

qe-bridge SiGe          # 1. Calculation + JSON export
qe-plot SiGe            # 2. Plot ε(ω)
qe-tcad SiGe diode      # 3a. Diode validation
qe-tcad SiGe transistor # 3b. Transistor validation

Run the full pipeline​

The main command is qe-bridge:

# Syntax
qe-bridge <chemical_formula>

# Examples
qe-bridge C      # Carbon (diamond)
qe-bridge Si     # Silicon
qe-bridge Ge     # Germanium
qe-bridge SiGe   # Silicon-germanium

Equivalent module mode:

python3 -m qe_to_tcad Si

Expected output​

✓ Structure downloaded: Diamond (Fd-3m)
✓ Pseudopotential: C_ONCV_PBE-1.0.upf
✓ SCF convergence succeeded
✓ NSCF calculations succeeded (1728 k-points)
✓ Epsilon extracted: epsilon_out/C_epsr.dat
✓ PNG figure: plots/C_dielectric_dispersion.png

Output directories​

FolderContent
generated_inputs/Generated QE .in files
epsilon_out/Raw epsilon.x results
convergence_data/JSON convergence traces
parsed_data/Structured JSON for TCAD
plots/300 DPI PNG figures

Visualize the dielectric function​

qe-plot SiGe
qe-plot C

Advanced scripts (source repository)​

If you work from the cloned repository:

# Terminal display (SSH-friendly)
python3 plotter.py epsilon_out/C_epsr.dat

# High-resolution PNG
python3 plotter.py epsilon_out/Si_epsr.dat --verbose
python3 plotter.py epsilon_out/Ge_epsr.dat --downsample 10

Convergence curves​

# Terminal display (source repository)
python3 plot_convergence_progressive.py convergence_data/C_convergence.json

# Also generates: plots/C_convergence_*.png

TCAD export (JSON)​

from fetcher import MaterialAnalyzer

analyzer = MaterialAnalyzer("Si")
data = analyzer.export_for_tcad()

import json
with open("Si_for_TCAD.json", "w") as f:
    json.dump(data, f, indent=2)

The JSON includes:

{
  "material": "Si",
  "epsilon_static": 12.047,
  "plasma_frequency_eV": 15.342,
  "energy_eV": [0.001, 0.002, "..."],
  "epsr_x": ["..."],
  "epsr_y": ["..."],
  "epsr_z": ["..."]
}

TCAD simulations (diode / transistor)​

qe-tcad SiGe diode
qe-tcad SiGe transistor

Advanced scripts (source repository)​

python3 plot_complet.py parsed_data/SiGe.json diode
python3 plot_complet.py parsed_data/SiGe.json transistor

See TCAD integration for more details.

Advanced options​

# Specify pw.x path
qe-bridge Si --pw /path/to/pw.x --nproc 4

# Light mode (fewer k-points, for tests)
python3 fetcher.py C --light_mode

See also​