Pressure engineering negative linear compressibility in various type systems

Various types of negative linear compressibility (NLC) under high pressure conditions were reported but not fully understood. NLC is a rare phenomenon where a crystal expands along one direction under hydrostatic compression. In this presentation, both crystalline and non-crystlline selenium samples were in situ studied in diamond anvil cell under high pressure conditions using synchrotron x-ray diffraction. Two types of NLC mechanism were found at various pressure regions, i. e. at around 10 GPa, and around 120 GPa, respectively, in this same elemental Se sample [1, 2]. By adjusting the preheating history of non-crystalline Se samples [3], we could capture early crystallization process and reveal the physics behind the previous controversy results on this system. Other type of NLC at very low pressure region, i. e. below 0.2 GPa, was also discovered in a Ni(II) complex single crystal [4], follow up with the similar phase transition at low temperature conditions. In practice, the latter case might have potentially bright application future.

References:
1. Shuhua Yuan, et al, Negative linear compressibility in Se at ultra-high pressure above 120 GPa, IUCrJ, 9, 253, 2022.
2. Kamil F. Dziubek, Negative linear compressibility at extreme pressure, IUCrJ, 9, 165, 2022.
3. Shuhua Yuan, et al, Early crystallization of amorphous selenium under high pressure studied by synchrotron XRD method, Journal of Physics: Condensed Matter, 35, 264003, 2023.
4. Boyang Fu, et al, Pressure-induced ferroelastic transition drives a large shape change in a Ni(II) complex single crystal, The Journal of Physical Chemistry Letters, 14 (16), 3891, 2023.