Dimensional reduction upon calcium incorporation in Cs0.3(Ca0.3Ln0.7)PS4 and Cs0.5(Ca0.5Ln0.5)PS4

A series of Ca-containing lanthanide thiophosphates has been obtained and their structural evolution from 3D for LnPS₄ and Cs_0.3(Ln_0.7Ca_0.3)PS₄ to 2D in Cs_0.5(Ln_0.5Ca_0.5)PS₄ was shown as a function of Ca content.

Experimental and theoretical studies of the ternary thiophosphate PbPS3 featuring ethane-like [P2S6]4- units

The ternary thiophosphate PbPS₃ was synthesized by a high-temperature solid-state reaction using PbS, P and S. Single-crystal X-ray diffraction analysis reveals that the compound crystallizes in the P2₁/c space group. It features a three-dimensional structure, which consists of [PbS₈] hendecahedra and isolated ethane-like [P₂S₆]^4- units. PbPS₃ can be easily obtained by different methods and shows high air stability, which is beneficial to its chemical synthesis and large-sized crystal growth. The crystal structure, optical properties and electronic structure of PbPS₃ have been researched by experimental methods and first-principles calculations. The results show that PbPS₃ has a moderate bandgap (E_{g. exp.} = 2.60 eV) and birefringence (Δn_cal. = 0.094@1064 nm), as well as a wide transparent range. Furthermore, to better understand the origin of the birefringence, structure comparisons and theoretical calculations were carried out. With a relatively high physicochemical stability and easy synthesis, PbPS₃ can be expected to be a prospective birefringent material.

Controlling the thermoelectric power of silicon–germanium alloys in different crystalline phases by applying high pressure

Si–Ge crystals are promising materials for use in various stress-controlled electronic junctions for next-generation nanoelectronic devices.