Hydrostatic pressure driven spin, volume and band gap collapses in SmFeO₃: a GGA + U study

Abstract

The crystal structure, magnetic and electronic properties of SmFeO₃ under hydrostatic pressure have been studied by first-principles calculations within the generalized gradient approximation plus Hubbard U (GGA + U). The iso-structural phase transition with spin, volume and band gap collapses can be induced by a large enough hydrostatic pressure. The high-spin (HS) state of Fe³⁺, with the magnetic moment of ~4 μ_B, is retained at low pressure. The spin crossover occurs at a transition pressure (~68 GPa) with the magnetic moment of Fe³⁺ decreasing to ~1 μ_B in low-spin (LS) state. Meanwhile, the reductions of cell volume (by ~−5.43%) and band gap (from >2 eV to ~1.6 eV) of SmFeO₃ are obtained when the HS–LS transition happens. Finally, the critical pressure of HS–LS transition, magnetic and electronic properties are found to be Hubbard U dependent.

Keywords:

• Rare-earth ferrites
• hydrostatic pressure
• spin transition
• first-principles

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51275198], [grant number 11274222], [grant number 51372149], and [grant number 51422503]; the National Key Basic Research Program of China [grant number 2015CB921600]; National Hi-tech Research and Development Program of China (863 Program) [grant number 2012AA041206]; Program for New Century Excellent Talents in University [grant number NCET-12-0238]; Specialized Research Fund for the Doctoral Program of Higher Education [grant number 20130061110026]; Patent Demonstration Project for Research Team in Jilin Province [grant number 20130416015ZG]; QiMingXing Project [grant number 14QA1402000] from Shanghai Municipal Science and Technology Commission; Eastern Scholar Program and ShuGuang Program [grant number 12SG34] from Shanghai Municipal Education Commission; Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (the second phase), and Shanghai Supercomputer Center are also acknowledged; Young Scientist Fund of Jilin Province of China [grant number 20150520108JH].