Pressure-induced phase transition in transition metal trifluorides

Abstract

As a fundamental thermodynamic variable, pressure can alter bonding patterns and drive phase transitions, leading to the creation of new high-pressure phases with exotic properties that are inaccessible at ambient pressure. Using swarm-intelligence structural prediction method, a phase transition of TiF3, from R-3c to Pnma phase, is predicted at high pressure, accompanied by the destruction of TiF6 octahedra and formation of TiF8 square antiprismatic units. Particularly, through laser-heated diamond anvil cell technique, the predicted Pnma phase of TiF3 is confirmed by high-pressure X-ray diffraction experiment. Furthermore, the in-situ electrical measurement indicates that the newly found Pnma phase has a semiconducting character, which is also consistent with electronic band structure calculations. We further show that this pressure-induced phase transition is a general phenomenon in ScF3, VF3, CrF3 and MnF3, offering valuable insights on the high-pressure phases in transition metal trifluorides.

Challenges and Strategies for Synthesizing High Performance Micro and Nanoscale High Entropy Oxide Materials

“…successfully prepared a HEO aerogel (Sm 0.2 Eu 0.2 Tb 0.2 Dy 0.2 Lu 0.2 ) 2 Zr 2 O 7 with a 3D porous network skeleton structure of pearl chain and an average particle size of 30–40 nm with a sol–gel template method followed by high‐temperature calcination and 3D structure reconstruction. [ 172 ] It had ideal high‐temperature insulation performance of 0.029–0.043 W (m K) −1 and a superior high specific surface area (80.37–443.26 m 2 g −1 ). Importantly, this HEO aerogel maintained single‐phase fluorite structure even after being heated to 1400 °C.…”