Ab initio prediction of pressure-induced structural phase transition of superconducting FeSe

作者：Rahman Gul^*; Kim In Gee; Freeman Arthur J

来源：Journal of Physics: Condensed Matter , 2012, 24(9): 095502.

DOI：10.1088/0953-8984/24/9/095502

External pressure driven phase transitions of FeSe are predicted using ab initio calculations. The calculations reveal that alpha-FeSe makes transitions to NiAs-type, MnP-type, and CsCl-type FeSe. Transitions from NiAs-type to MnP-type and CsCl-type FeSe are also predicted. MnP-type FeSe is also found to be able to transform to CsCl-type FeSe, which is easier from alpha-FeSe than the transition to MnP-type FeSe, but comparable to the transition from NiAs-type FeSe. The calculated electronic structures show that all phases of FeSe are metallic, but the ionic interaction between Fe-Se bonds becomes stronger and the covalent interaction becomes weaker when the structural phase transition occurs from alpha-FeSe to the other phases of FeSe. The experimentally observed decrease in T-c of superconducting alpha-FeSe at high pressure may be due to a structural/magnetic instability, which exists at high pressure. The results suggest an increase of the Tc of alpha-FeSe if such phase transitions are frustrated by suitable methods.

• 出版日期2012-3-7
• 单位西北大学