Pressure-Induced High-κ Dielectric Properties and Multiple Phase Transitions between Novel Nonperovskite and Perovskite Phases in LiSbO₃: A First-Principles Study

Abstract

The pressure effects on LiSbO3 have been investigated via first-principles simulation. Multiple pressure-induced reconstructive phase transitions between nonperovskite and perovskite states are revealed, i.e., undergoing Pncn-to-R3c-to-P6322-to-Sb:A Pnma-to-P63/m phase transitions with increasing pressure. New nonperovskite P6322 and P63/m states, not present on experiment, can form a reversible transformation (belonging to displacive-/quasi-reconstructive transition in nature) with the increase and decrease of pressure, involving indirect softening of two unstable phonon modes via symmetry analysis. The anomalous formation of a novel Sb:A Pnma state, instead of the Sb:B Pnma state as we commonly expected, is also revealed and explicated by the change of Li–O and Sb–O bonds as well as the limit of the typical tolerance factors. The dielectric response and anomalous larger band gap under a high pressure are also accompanied by the change of direct-to-indirect band gap. All of these findings stimulate interest in the exploration and experimental confirmation of such novel and diverse nonperovskite and perovskite structures as well as their optical applications.

Insight into the Structural, Optical and Mechanical Properties of RbSnX3 (X = Cl, Br, I) under High Pressure

“…On the other hand, recent studies have suggested hydrostatic pressure as a green and effective method to effectively tune the crystal structure, improve the optoelectronic properties, and even make the material metalized to produce superconductivity. − As an example, Tian et al found that the crystal structure underwent a transition from a perovskite state to a post-post-perovskite state under hydrostatic pressure accompanied by significant piezochromic effects . In addition, Ke et al verified the piezochromic effects of CsPbI 3 in a high-pressure experiment .…”

Theoretical study on the ferroelectric and light absorption properties of Li2SbBiO6 for harvesting visible light

“…16 Rich structural phase transitions can appear in LiSbO 3 at different pressures with large static dielectric tensor and insulating properties. 17 LiSbO 3 with a R3c structure has a large bandgap and mainly absorbs ultraviolet light according to our recent study. 18 LiBiO 3 with the Pccn space group can be prepared via the hydrothermal treatment method.…”

“…The elasticity coefficient of R 3 c -LiSbO 3 calculated using the PBE function is smaller than that of the SCAN function (Table 2), 18 and the elasticity coefficient becomes larger under high pressure conditions according to reports in the literature. 17,18 All elasticity coefficients of R 3 c -LiSbO 3 and R 3-Li 2 SbBiO 6 in Table 2 meet the stability conditions. The eigenvalue matrices of the elastic coefficients of LiSbO 3 and Li 2 SbBiO 6 in Table 3 are greater than 0 and satisfy the mechanical stability condition.…”