Ferroelectricity in Dion–Jacobson ABiNb₂O₇(A = Rb, Cs) compounds

Abstract

Ferroelectricity and piezoelectricity in CsBiNb2O7 are demonstrated for the first time.

Emergent Noncentrosymmetry and Piezoelectricity Driven by Oxygen Octahedral Rotations in n = 2 Dion–Jacobson Phase Layer Perovskites

“…First-principles density functional theory (DFT) calculations show that the symmetry can be broken and ferroelectric properties can be achieved with a combination of layered cation ordering and OORs. [ 15,16 ] Recently, an n = 1 Ruddlesden-Popper family (Na R TiO 4 ; R = rare earth) was experimentally determined to be piezoelectric, yet nonpolar. [ 9 ] To date, there is only a small group of well-characterized layered oxide ferroics, which include some Aurivillius phases (e.g., SrBi 2 Ta 2 O 7 [ 10 ] and its derivatives, [ 11 ] and CaBi 2 Nb 2 O 9 [ 12 ] ), a Ruddlesden-Popper phase Sr n +1 Ti n O 3 n +1 ( n = 1-6), [ 13 ] and the Dion-Jacobson (DJ) phases RbBiNb 2 O 7 , [ 14 ] CsNdNb 2 O 7 , [ 15 ] and CsBiNb 2 O 7 .…”

Photocatalytic activity of 2D nanosheets of ferroelectric Dion–Jacobson compounds

“…Their unique structure leads to many interesting properties, making them of interest for many applications, including for solar cells, 1,2 water splitting 3,4 and ferroelectrics. [5][6][7] It is known that DJ phase materials can be exfoliated into nanosheets due to the large interlayer spacing and weak bonding of the A 0 layers. M. Hojamberdiev et al 3 exfoliated the centrosymmetric, non-polar, three-layer compound CsBa 2 Ta 3 -O 10 by a sequence of steps involving nitridation-protonationintercalation to produce nanosheets.…”

“…Recently, exciting new results have emerged that demonstrate ferroelectricity in the non-centrosymmetric, polar, twolayer DJ phase ABiNb 2 O 7 (A ¼ Rb, Cs). 6,7 Like some simple perovskites (e.g. BaTiO 3 ), their spontaneous polarization originates from displacement of the A-site cations and tilting of the octahedra.…”

“…17 The spontaneous polarization of CsBiNb 2 O 7 (a ¼ 5.4964, b ¼ 5.4223 and c ¼ 11.3704Å) and RbBiNb 2 O 7 (a ¼ 5.4193, b ¼ 5.3589 and c ¼ 11.2099Å) were calculated to be around 0.438 and 0.47 C m À2 , respectively. 7 It is of great interest to investigate the potential photocatalytic properties of these highly-polar materials. The possibility of being able to produce them as nanosheets by exfoliation offers the potential to generate high-surface-area catalyst materials that have polar ferroelectric domains.…”

Phase Transition Behavior of the Layered Perovskite CsBi0.6La0.4Nb2O7: A Hybrid Improper Ferroelectric

“…Our follow-up experimental studies [16] on CsBiNb 2 O 7 suggested that ferroelectricity was hindered by moisture uptake, leading to proton conductivity and leakage. Nevertheless, a more recent work by Chen et al [17] did provide experimental evidence for ferroelectricity in this compound. Goff et al [16], attempted to determine any high temperature phase transitions in CsBiNb 2 O 7 using powder neutron diffraction: no evidence for phase transitions was identified up to 900 • C, above which sample deterioration precluded further study.…”