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arXiv · 2408.15105

Resolving the pressure induced 'self-insertion' in skutterudite CoSb3

Bihan Wang·Anna Pakhomova·Saiana Khandarkhaeva·Mirtha Pillaca·Peter Gille·Zhe Ren·Dmitry Lapkin·Dameli Assalauova·Pavel Alexeev·Ilya Sergeev·Satishkumar Kulkarni·Tsu-Chien Weng·Michael Sprung·Hanns-Peter Liermann·Ivan A. Vartanyants·Konstantin Glazyrin
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Abstract

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.

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Bihan Wang, Anna Pakhomova, Saiana Khandarkhaeva, Mirtha Pillaca, Peter Gille, Zhe Ren, Dmitry Lapkin, Dameli Assalauova, Pavel Alexeev, Ilya Sergeev, Satishkumar Kulkarni, Tsu-Chien Weng, Michael Sprung, Hanns-Peter Liermann, Ivan A. Vartanyants, Konstantin Glazyrin. 2024-08-27. Resolving the pressure induced 'self-insertion' in skutterudite CoSb3. https://arxiv.org/abs/2408.15105

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