CoSb3, a skutterudite compound, is key in studying thermoelectric materials. Under compression, it undergoes a 'self-insertion' isostructural transition, redistributing large Sb atoms among crystallographic sites. We investigated CoSb3's structural stability up to 70 GPa using single crystal X-ray diffraction and high-resolution X-ray scattering, including Bragg Coherent Diffraction Imaging. We examined the material in three pressure transmitting media (PTMs), exploring how PTMs and nonhydrostatic stresses affect CoSb3. Notably, the 'self-insertion' transition may reduce or even make compressibility negative. Additionally, we report a previously unknown phase transformation from cubic Im-3 to trigonal R-3 above 40 GPa and discuss the phases' distinctive behaviors.
@article{arxiv.2408.15105,
title = {Resolving the pressure induced 'self-insertion' in skutterudite CoSb3},
author = {Bihan Wang and Anna Pakhomova and Saiana Khandarkhaeva and Mirtha Pillaca and Peter Gille and Zhe Ren and Dmitry Lapkin and Dameli Assalauova and Pavel Alexeev and Ilya Sergeev and Satishkumar Kulkarni and Tsu-Chien Weng and Michael Sprung and Hanns-Peter Liermann and Ivan A. Vartanyants and Konstantin Glazyrin},
journal= {arXiv preprint arXiv:2408.15105},
year = {2024}
}