---
pretty_name: Phonix Database

arxiv:
- arXiv:2504.21245

tags:
- materials
- phonon
- thermal-conductivity
- first-principles

license: cc-by-4.0
---

Summary of the Phonix database
==============================

The files on this page are a summary of
[the Phonix database](https://huggingface.co/datasets/phonix-hub/Phonix).


Column descriptions of `summary.csv`
--------------------------------------

| Column | Description |
|--------|-------------|
| `mp_id` |  Materials Project ID (e.g. mp-149 for Si diamond) |
| `unique_id` |  Unique entry identifier |
| `formula` |  Chemical formula (e.g. Si, MgO, BeTe) |
| `spg_number` |  International space group number (e.g. 227 for diamond silicon) |
| `natoms_prim` |  Number of atoms in primitive cell |
| `natoms_conv` |  Number of atoms in conventional cell |
| `natoms_sc` |  Number of atoms in supercell for force constant calculations |
| `trans_conv2prim` |  Transformation matrix: conventional to primitive cell (JSON 3x3) |
| `trans_conv2sc` |  Transformation matrix: conventional to supercell (JSON 3x3) |
| `structure` |  Crystal structure JSON (cell, positions, symbols, pbc) |
| `volume[A^3]` |  Cell volume in cubic angstroms |
| `nac` |  Non-analytical correction flag (0: no NAC, 1: damping method, 2: mixed-space approach, 3: Ewald method) |
| `volume_relaxation` |  Additional volume relaxation flag (0: no additional relaxation, 1: additionally relaxed) |
| `scph` |  Self-consistent phonon (SCPH) flag |
| `four` |  4-phonon scattering flag |
| `modulus[GPa]` |  Bulk modulus [GPa] |
| `fc2_error[%]` |  2nd-order (Harmonic) force constants fitting error [%] |
| `fc3_error[%]` |  3rd-order (Cubic) force constants fitting error [%] |
| `fc_higher_error[%]` |  Higher-order force constants fitting error [%] |
| `kp[W/mK]` |  Particle contribution to lattice thermal conductivity [W/mK] |
| `kc[W/mK]` |  Coherence contribution to lattice thermal conductivity [W/mK] |
| `klat[W/mK]` |  Total lattice thermal conductivity (kp+kc) [W/mK] |
| `qmesh` |  q-point mesh for the Boltzmann transport equation (e.g. '19x19x19') |
| `qmesh_density` |  q-point mesh density |
| `min_phfreq[cm^-1]` |  Minimum phonon frequency [cm^-1] |
| `max_phfreq[cm^-1]` |  Maximum phonon frequency [cm^-1] |
| `phfreq[cm^-1]` |  Phonon frequency grid points (JSON array, shape=[51]) |
| `phdos[a.u.]` |  Total phonon density of states (JSON array, shape=[51]) |
| `pdos[a.u.]` |  Element-projected phonon DOS (JSON dict of arrays) |
| `kspec_freq[W/mK/cm^-1]` |  Spectral thermal conductivity (kp) vs frequency (JSON array) |
| `kcumu_norm_freq` |  Normalized cumulative kappa (kp) vs frequency (JSON array) |
| `mfp[nm]` |  Mean-free-path grid (JSON array) |
| `log10[mfp[nm]]` |  Log10 of mean-free-path grid (JSON array) |
| `kspec_mfp[W/mK/nm]` |  Spectral thermal conductivity vs MFP (JSON array) |
| `kcumu_norm_mfp` |  Normalized cumulative kappa vs MFP (JSON array) |
| `calc_time[sec]` | Computational time [sec] |


### Note

- The transformation matrix is defined using the [Phonopy](https://phonopy.github.io/phonopy/setting-tags.html#primitive-axes-tag) convention.
- The anharmonic properties correspond to the values at 300 K.
- Please refer to the [official ALAMODE page](https://alamode.readthedocs.io/en/latest/faq.html) for details on the fitting error.