How do I install the Tb2j skill?

Run npx skillmds@latest add tomevault-io/tb2j in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Tb2j?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

tomevault-io (@tomevault-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Tb2j by tomevault-io — Agent Skill

Name: Tb2j
Author: tomevault-io

Tb2j

Guide for using TB2J command-line tools to calculate magnetic interaction parameters (J, DMI, etc.) from DFT outputs (Wannier90, Siesta, Abacus). Use this skill when the user asks about running TB2J commands, their parameters, inputs, or outputs. Use when this capability is needed.

tomevault-io Updated Sep 17, 2026

File contents

TB2J Skill

This skill provides expert guidance on using the TB2J package to calculate magnetic interaction parameters (Heisenberg exchange $J$, DMI $D$, Anisotropy $J_{ani}$) from DFT inputs.

References

Command Reference: Detailed flags and arguments for all scripts (wann2J.py, siesta2J.py, etc.).
Workflows & DFT Prep: Step-by-step guides for preparing VASP/Wannier90/Siesta inputs.
Conventions: Vital information on Hamiltonian signs, units, and spin normalization.
Outputs: Explanations of exchange.out, exchange.xml, and interfaces to Vampire/Multibinit.

Common Workflows

1. Wannier90 (VASP, QE, Abinit)

Command: wann2J.py
Key Step: Ensure projections in .win file cover magnetic orbitals.
See: Workflows > Wannier90

2. Siesta

Command: siesta2J.py
Key Step: Set SaveHS True in .fdf.
See: Workflows > Siesta

3. Abacus

Command: abacus2J.py
Key Step: Set out_mat_hs2 1 in INPUT.
See: Workflows > Abacus

4. Non-Collinear / Anisotropy

Option A: Full non-collinear DFT + wann2J.py --spinor.
Option B: "Rotate and Merge" using TB2J_rotate.py (generate structures) -> DFT -> TB2J_merge.py (combine results).
See: Workflows > Non-Collinear

Troubleshooting / FAQ

Results contradict experiment?
- Check Conventions. Are you comparing $J$ vs $2J$?
- Verify the Fermi Energy (--efermi) matches the DFT calculation exactly.
- Is the system metallic? Try increasing K-mesh or adjusting --nz.
Wannier functions not localized?
- Check wannier90.wout for spreads.
- Adjust dis_win (outer window) to include all relevant bands.
- Check projections.
"Orbitals not found" error?
- Ensure --elements matches the atoms in the structure file.
- Check if exclude_orbs is needed for semi-core states.

Source: mailhexu/TB2J — distributed by TomeVault.

---name: tb2jdescription: Guide for using TB2J command-line tools to calculate magnetic interaction parameters (J, DMI, etc.) from DFT outputs (Wannier90, Siesta, Abacus). Use this skill when the user asks about running TB2J commands, their parameters, inputs, or outputs. Use when this capability is needed.---# TB2J SkillThis skill provides expert guidance on using the TB2J package to calculate magnetic interaction parameters (Heisenberg exchange $J$, DMI $D$, Anisotropy $J_{ani}$) from DFT inputs.## References* **[Command Reference](references/commands.md)**: Detailed flags and arguments for all scripts (`wann2J.py`, `siesta2J.py`, etc.).* **[Workflows & DFT Prep](references/workflows.md)**: Step-by-step guides for preparing VASP/Wannier90/Siesta inputs.* **[Conventions](references/conventions.md)**: Vital information on Hamiltonian signs, units, and spin normalization.* **[Outputs](references/outputs.md)**: Explanations of `exchange.out`, `exchange.xml`, and interfaces to Vampire/Multibinit.## Common Workflows### 1. Wannier90 (VASP, QE, Abinit)* **Command**: `wann2J.py`* **Key Step**: Ensure `projections` in `.win` file cover magnetic orbitals.* **See**: [Workflows > Wannier90](references/workflows.md#1-wannier90-workflow-general)### 2. Siesta* **Command**: `siesta2J.py`* **Key Step**: Set `SaveHS True` in `.fdf`.* **See**: [Workflows > Siesta](references/workflows.md#2-siesta-workflow)### 3. Abacus* **Command**: `abacus2J.py`* **Key Step**: Set `out_mat_hs2 1` in `INPUT`.* **See**: [Workflows > Abacus](references/workflows.md#3-abacus-workflow)### 4. Non-Collinear / Anisotropy* **Option A**: Full non-collinear DFT + `wann2J.py --spinor`.* **Option B**: "Rotate and Merge" using `TB2J_rotate.py` (generate structures) -> DFT -> `TB2J_merge.py` (combine results).* **See**: [Workflows > Non-Collinear](references/workflows.md#4-non-collinear--spin-orbit-coupling-soc)## Troubleshooting / FAQ* **Results contradict experiment?** * Check [Conventions](references/conventions.md). Are you comparing $J$ vs $2J$? * Verify the **Fermi Energy** (`--efermi`) matches the DFT calculation exactly. * Is the system metallic? Try increasing K-mesh or adjusting `--nz`.* **Wannier functions not localized?** * Check `wannier90.wout` for spreads. * Adjust `dis_win` (outer window) to include all relevant bands. * Check projections.* **"Orbitals not found" error?** * Ensure `--elements` matches the atoms in the structure file. * Check if `exclude_orbs` is needed for semi-core states.---> Source: [mailhexu/TB2J](https://github.com/mailhexu/TB2J) — distributed by [TomeVault](https://tomevault.io).

Frequently asked questions