spgrep-modulation

基于不可约空间群表示的集体原子调制分析

• Github: https://github.com/phonopy/spgrep-modulation
• 文档: https://phonopy.github.io/spgrep-modulation
• 文档(开发): https://phonopy.github.io/spgrep-modulation/develop/
• PyPI: https://pypi.ac.cn/project/spgrep-modulation

功能

• 计算由声子本征模形成的表示矩阵和不可约表示
• 计算空间群不可约表示的各向同性子群的自动计算
• 在选定的各向同性子群的序参量方向上生成调制结构

用法

from pathlib import Path
import phonopy
from phonopy.structure.symmetry import Symmetry
from spgrep_modulation.modulation import Modulation

# Load Phonopy object
path = Path(__file__).resolve().parent.parent / "tests" / "phonopy_mp-2998.yaml.xz"
ph = phonopy.load(path)

# Prepare Modulation class
qpoint = [0.5, 0, 0]  # X point
md = Modulation.with_supercell_and_symmetry_search(
    dynamical_matrix=ph.dynamical_matrix,
    supercell_matrix=[2, 2, 2],
    qpoint=qpoint,
    factor=ph.unit_conversion_factor,
)

# Degenerated imaginary mode
frequency_index = 0
print(f"Frequency (THz): {md.eigvals_to_frequencies(md.eigenspaces[frequency_index][0]):.2f}")
# -> Frequency (THz): -4.88
print(f"Irrep shape: {md.eigenspaces[frequency_index][2].shape}")
# -> Irrep shape: (16, 2, 2)

# Modulated cells corresponding to one-dimensional order-parameter directions of isotropy subgroup
cells = md.get_high_symmetry_modulated_supercells(frequency_index)
for cell in cells:
    symmetry = Symmetry(cell)
    print(f"{symmetry.dataset['international']} (No. {symmetry.dataset['number']})")
# -> Pmma (No. 51) and Cmcm (No. 63)

安装

pip install spgrep-modulation

conda create -n spgrep python=3.10 pip
conda activate spgrep
git clone git@github.com:lan496/spgrep-modulation.git
cd spgrep-modulation
pip install -e .
# pip install -e ".[dev,docs,vis]"
# pre-commit install

许可证

spgrep-modulation是在BSD 3-clause许可证下发布的。

开发

文档

sphinx-autobuild docs docs_build
# open localhost:8000 in your browser

致谢

一些测试文件tests/phonopy_mp-*.yaml.xz是从phonondb根据CC BY 4.0改编的。