# How to cite phonopy#

## Citation of phonopy#

If you have used phonopy, please cite the following articles, which indeed helps the phonopy project to continue:

“Implementation strategies in phonopy and phono3py”,

Atsushi Togo, Laurent Chaput, Terumasa Tadano, and Isao Tanaka, J. Phys. Condens. Matter

**35**, 353001-1-22 (2023)https://dx.doi.org/10.1088/1361-648X/acd831 (Open access)

@article{phonopy-phono3py-JPCM, author = {Togo, Atsushi and Chaput, Laurent and Tadano, Terumasa and Tanaka, Isao}, title = {Implementation strategies in phonopy and phono3py}, journal = {J. Phys. Condens. Matter}, volume = {35}, number = {35}, pages = {353001}, year = {2023}, doi = {10.1088/1361-648X/acd831} }

“First-principles Phonon Calculations with Phonopy and Phono3py”,

Atsushi Togo, J. Phys. Soc. Jpn.,

**92**, 012001-1-21 (2023)https://doi.org/10.7566/JPSJ.92.012001 (Open access)

@article{phonopy-phono3py-JPSJ, author = {Togo, Atsushi}, title = {First-principles Phonon Calculations with Phonopy and Phono3py}, journal = {J. Phys. Soc. Jpn.}, volume = {92}, number = {1}, pages = {012001}, year = {2023}, doi = {10.7566/JPSJ.92.012001} }

## Some papers where phonopy was used#

`phonopy-qha`

: Thermal properties, quasi-harmonic approximation used for thermal expansion#

“First-principles phonon calculations of thermal expansion in Ti3SiC2, Ti3AlC2, and Ti3GeC2”,

Atsushi Togo, Laurent Chaput, Isao Tanaka, Gilles Hug, Phys. Rev. B,

**81**, 174301-1-6 (2010)

`MODULATION`

tag: Collective atomic modulation, symmetry breaking#

“Evolution of crystal structures in metallic elements”,

Atsushi Togo and Isao Tanaka, Phys. Rev. B,

**87**, 184104-1-6 (2013)“Transition pathway of CO2 crystals under high pressures”,

Atsushi Togo, Fumiyasu Oba, and Isao Tanaka, Phys. Rev. B,

**77**, 184101-1-5 (2008)“Inversion Symmetry Breaking by Oxygen Octahedral Rotations in the Ruddlesden-Popper NaRTiO4 Family”,

Hirofumi Akamatsu, Koji Fujita, Toshihiro Kuge, Arnab Sen Gupta, Atsushi Togo, Shiming Lei, Fei Xue, Greg Stone, James M. Rondinelli, Long-Qing Chen, Isao Tanaka, Venkatraman Gopalan, and Katsuhisa Tanaka, Phys. Rev. Lett.

**112**, 187602-1-5 (2014)“First-principles calculations of the ferroelastic transition between rutile-type and CaCl2-type SiO2 at high pressures”,

Atsushi Togo, Fumiyasu Oba, and Isao Tanaka, Phys. Rev. B,

**78**, 134106 (2008)

## A short history of phonopy#

Phonopy development started to replace and extend fropho (http://fropho.sourceforge.net/). The implementation of fropho is also based on Parlinski-Li-Kawazoe method. Although fropho was implemented from scratch except for the symmetry finder and input file parser, to start the development, it was motivated by the existence of PHON code. The important part of the implementation is the symmetry handling. In fropho, at first the symmetry finder in Abinit code was employed, but later the symmetry finder was replaced by spglib (https://spglib.github.io/spglib/).