Synthesis, Structure, and Properties of Turbostratically Disordered (PbSe)_1.18(TiSe₂)₂

Abstract

Synthesis and structural characterization of a turbostratically disordered polymorph of (PbSe)1.18(TiSe2)2 is reported. The structure of this compound consists of an intergrowth between one distorted rock salt structured PbSe bilayer and two transition metal dichalcogenide structured Se–Ti–Se trilayers. In addition to the lattice mismatch, there is extensive rotational disorder between these constituents. The electrical resistivity of (PbSe)1.18(TiSe2)2 is a factor of 9 lower at room temperature, and the Seebeck coefficient is almost double that reported for the crystalline misfit layered compound analogue.

Insights from STEM and NBED studies into the local structure and growth mechanism of misfit layered compounds prepared using modulated reactants

“…Since the hk0 reflections do not contain any information on the stacking order, the layers could be stacked in a random order, but with specific rotational relationships between them. This is consistent with the report by Atkins on the growth of transition metal diselenide films from layered precursors and agrees with the extrapolation of their findings [25]. The 12-fold symmetry also implies that within the beam size of the NBED experiment, there must be crystalline domains where there is a coincidence of the 3-fold symmetry axis of the dichalcogenide layer and the 4-fold axis of the square structure of the SnSe layer.…”

“…In plane X-ray diffraction patterns contain Bragg maxima that can be indexed as hk0 maxima of the independent constituent layers. In contrast to most of the misfit layered compounds formed via high temperature reactions, the in plane structures of structures grown using this new technique do not appear to distort to achieve one or more commensurate axes, even when samples of the same composition have been prepared in an ordered polymorph using traditional high temperature synthesis techniques [25]. For [(SnSe) 1.15 ] 1 (VSe 2 ) 1 prior X-ray investigations yielded a c lattice parameter of 1.203(1) nm, a square in plane a-lattice parameter of 0.593(1) nm for the SnSe constituent and a hexagonal in plane a-lattice parameter of 0.341(1) nm for the VSe 2 constituent.…”

The kinetic effect on formation of disordered intergrowth structures in mixed bismuth-layered (Bi3NbTiO9)2(Bi4Ti3O12)1 compounds

“…The layered intergrowth structures commonly exist in inorganic solid compounds and have long been widely interested because of a variety of novel properties, such as high-temperature superconductivity, high-temperature piezoelectricity, colossal magnetoresistance and low thermal conductivity [1][2][3][4][5]. The intergrowth bismuth-layered structures are one of the most important systems among these compounds, which are built up by the regular stacking of two different bismuth layered blocks (Bi 2 O 2 ) 2 þ (A mÀ 1 B m O 3m þ 1 ) 2À and (Bi 2 O 2 ) 2 þ (A nÀ 1 B n O 3n þ 1 ) 2À , always with n=mþ 1 and mainly with Bi to occupy A sites [6][7][8].…”

Characterization of Cr-rich Cr-Sb multilayer films: Syntheses of a new metastable phase using modulated elemental reactants

“…The MER approach has been used successfully for the synthesis of new, metastable compounds [15][16][17][18][19][20]. This technique was also previously used to explore metastable transition metal antimonides Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jssc as well as various other binary and ternary compounds based on Cr-Sb, Fe-Sb, Ru-Sb, Ni-Sb or Cu-Cr-Se [21][22][23][24][25][26][27][28][29][30], making this a promising approach to the targeted compound.…”