LinReTraCe

Official Resources

• Homepage: https://github.com/linretracedev/linretrace
• Documentation: https://github.com/linretracedev/linretrace/wiki (or minimal docs on repo)
• Source Repository: https://github.com/linretracedev/linretrace
• License: GPLv3

Overview

LinReTraCe (Linear Response Transport Centre) is a massively parallel code for calculating transport properties of solids. It is specifically designed to work with spectral functions from many-body calculations (like DMFT), capturing lifetime effects and renormalization beyond the constant relaxation time approximation.

Scientific domain: Quantum transport, Thermoelectrics, Correlated materials Target user community: DMFT practitioners, Thermoelectricity researchers

Theoretical Methods

• Linear Response Theory (Kubo formalism)
• Boltzmann Transport Equation (with energy/momentum dependent lifetimes)
• Optical conductivity
• Seebeck coefficient
• Thermal conductivity
• Hall effect (some versions)
• Integration over Brillouin Zone

Capabilities (CRITICAL)

• Transport Coefficients: DC/Optical conductivity, Seebeck, Thermal conductivity.
• Many-Body Inputs: Accepts self-energies or spectral functions from DMFT.
• Interfaces: Works with Wien2k, VASP, and Wannier90 inputs.
• Parallelization: MPI parallelization for efficient k-space integration.
• Verification: Artifact-free integration schemes.

Key Features

DMFT-Transport Link:

• Bridges the gap between DMFT electronic structure and experimental transport observables.
• Handles frequency-dependent self-energies.

Efficiency:

• Written in Fortran/C++.
• Optimized for large k-grids required for transport convergence.

HDF5 Output:

• All results are stored in structured HDF5 files for efficient data management and analysis.

Inputs & Outputs

• Input formats:
  • LINRETRACE.in (aka config.lrtc): Free-format configuration file defining calculation parameters, temperature range, and desired observables.
  • Electronic structure data (eigenvalues, velocities) from DFT/Wannier.
  • Self-energy $\Sigma(\omega)$ from DMFT.
• Output data types:
  • HDF5 files (*.h5) containing:
    • Transport tensors ($\sigma$, $S$, $\kappa$) vs Temperature or Chemical Potential.
    • Optical conductivity spectra $\sigma(\omega)$.
  • lprint tool provided to extract/plot data from HDF5 files.

Interfaces & Ecosystem

• Upstream: Reads data from Wien2k, VASP, Wannier90.
• Downstream: Produces HDF5 data; analysis via lprint or h5py (Python).

Workflow and Usage

1. Perform DFT+DMFT calculation.
2. Generate Wannier functions or use DFT velocities.
3. Export Self-energy.
4. Configure LINRETRACE.in with desired T-mesh and chemical potential range.
5. Run LinReTraCe to integrate Kubo formulas over the BZ.
6. Use lprint to visualize the transport coefficients from the HDF5 output.

Performance Characteristics

• Scaling: Scales well with k-points via MPI.
• Accuracy: Sophisticated integration tetrahedrons/adaptive schemes to handle Fermi surface complexity.

Comparison with Other Codes

• vs BoltzTraP: BoltzTraP uses constant relaxation time (semi-classical); LinReTraCe captures lifetime effects and renormalization from self-energies.
• vs BoltzWann: Similar Wannier-based approach, but LinReTraCe focuses on linear response with full self-energy inputs.
• vs TRIQS/transport: LinReTraCe is a dedicated standalone transport code optimized for large k-grids.
• Unique strength: Handling of frequency-dependent self-energies (lifetimes) in transport coefficients.

Verification & Sources

Primary sources:

1. GitHub Repository: https://github.com/linretracedev/linretrace
2. Publication: "LinReTraCe: The Linear Response Transport Centre", arXiv/PRB.

Verification status: ✅ VERIFIED

• Source code: OPEN (GitHub)
• Integration: Standard link to DMFT and Wannier workflows
• Focus: Dedicated transport post-processing