Systematic prediction of new ferroelectrics in space groups P3₁ and P3₂

Abstract

Release 2002/2 of the Inorganic Crystal Structure Database (FIZ Karlsruhe, Germany, and Institute Laue-Langevin, Grenoble, France) contains 62 entries in space group P3(1) and ten entries in space group P3(2) for 49 different materials including eight families with two or more isostructural members. The structural criteria for ferroelectricity are satisfied for 16 new structure types at a confidence level that depends on the reliability of each determination. LaBGeO(5), a mineral with stillwellite structure, was previously reported as ferroelectric and forms an additional family with seven other members or related structures that satisfy the criteria. Ten structures reported in space group P3(1) or P3(2) are dubious or incorrect, with atomic coordinates that satisfy supergroup symmetry. One material is probably pyroelectric but is unlikely to become ferroelectric, and three others are either incompletely solved or incompletely refined. Among the predicted new ferroelectrics are Cu(2)BaGeS(4,) Fe(3)(Fe,Si)O(4)(OH)(5), Se(4)S(5), K(2)HCr(2)AsO(10), IV-RbNO(3), Rb(2)Sc(NO(3))(5), Na(3)ReO(5), Nd(14)(GeO(4))(2)(BO(3))(6)O(8), CsHgCl(3,) Ba(2)Cu(2)AlF(11), KYF(4), SrS(2)O(6).4H(2)O, Cu(3)PbTeO(6)(OH)(2), ReH(CO)(4), Ni(2)(NH(3))(9)Mo(CN)(8).2H(2)O and the 6T polytype of Ca(1.89)Ta(1.80)Sm(0.16)Ti(0.10)O(7), in addition to beta-LaBSiO(5), PbBAsO(5) and BaBAsO(5) in the stillwellite family.

Oxygenated CdS Buffer Layers Enabling High Open‐Circuit Voltages in Earth‐Abundant Cu2BaSnS4 Thin‐Film Solar Cells

“…Earth‐abundant and air‐stable thin‐film materials are regarded as one promising option to meet the increasing demand for low‐cost solar cell manufacturing. Earth‐abundant Cu 2 BaSnS 4 (CBTS), crystallizing into the trigonal symmetry with a space group of either P 3 1 , P 3 1 21, or P 3 2 21, has emerged as a promising low‐cost solar energy material and has attracted the attention of the academic community. Its noncentrosymmetric crystal structure, along with the large atomic size differences among the constituent cation elements, endow CBTS with more beneficial defect properties for efficient photovoltaic and photoelectrochemical solar energy conversion than kesterite Cu 2 ZnSnS 4 (CZTS) .…”

Physics‐Guided Data‐Mining Driven Design of Room‐Temperature Multiferroic Perovskite Oxides

“…This distance ( r ) of acentric displacement is a good descriptor for predicting ferroelectric structural phase transition and provides atomic scale origin of ferroelectricity in perovskites via and , respectively . Abrahams and Balachandran et al ever used a criterion of r > 0 to guide searching for new inorganic ferroelectrics. In perovskite oxides, ferroelectric acentric displacement is a collective result of atom packing system under thermodynamic boundary conditions (e.g., temperature or/and pressure).…”

Crystal structures and stability of trigonal KLnF4fluorides (Ln = Y, Ho, Er, Tm, Yb)

“…14,28 We are generally interested in the crystal structures and stabilities of the AMF 4 materials (A = Li, Na, K; M = Y, rare earth) that are related to the fluorite structure with various schemes of cation (dis)ordering. [29][30][31][32][33][34] A series of studies at various conditions has previously been carried out on KY 3 F 10 that is a related material to KYF 4 in the system KF-YF 3 . At ambient pressure and room temperature, it is an anion-excess 2 × 2 × 2 superstructure of fluorite in space group Fm3m, a = 11.553(1) Å.…”

“…[1][2][3][4] The cations in KYF 4 are distributed in three layers perpendicular to the c axis. Within the layers, chains of Y 2 F 12 groups formed by two [YF 7 ] pentagonal bipyramids alternate with chains of edge-shared distorted [KF 8 ] cubes.…”

“…In this work, we use synchrotron radiation to re-examine the crystal structure of KYF 4 in view of the inconsistencies between the structural models [1][2][3][4] and some spectroscopic data, in which space group P3 1 12 was assumed but not confirmed with the X-ray data. 25 In addition, the structures of the 4 , prepared by grinding some of the single crystals, was studied at atmospheric pressure with X-ray powder diffraction at the ANKA Synchrotron Light Source in Karlsruhe.…”