The environmental accumulation of plastic is a huge problem due to its low degradability.

The BaAl 4 prototype structure and its derivatives have been identified to host several topological quantum materials and noncentrosymmetric superconductors. Single crystals up to ∼3 mm × 3 mm × 5 mm of Ln 2 Co 3 Ge 5 (Ln = Pr, Nd, and Sm) are obtained via flux growth utilizing Sn as metallic flux. The crystal structure is isostructural to the Lu 2 Co 3 Si 5 structure type in the crystallographic space group C2/c. The temperature-dependent magnetization indicates magnetic ordering at 30 K for all three compounds. Pr 2 Co 3 Ge 5 and Nd 2 Co 3 Ge 5 exhibit complex magnetic behavior with spin reorientations before ordering antiferromagnetically around 6 K, whereas Sm 2 Co 3 Ge 5 shows a clear antiferromagnetic behavior at 26 K. The structures and properties of Ln 2 Co 3 Ge 5 (Ln = Pr, Nd, and Sm) are compared to those of the ThCr 2 Si 2 and BaNiSn 3 structure types. Herein, we present the optimized crystal growth, structure, and physical properties of Ln 2 Co 3 Ge 5 (Ln = Pr, Nd, and Sm).

Strongly correlated electrons in layered perovskite structures have been the birthplace of high-temperature superconductivity, spin liquids, and quantum criticality. Specifically, the cuprate materials with layered structures made of cornersharing square-planar CuO 4 units have been intensely studied due to their Mott insulating ground state, which leads to high-temperature superconductivity upon doping. Identifying new compounds with similar lattice and electronic structures has become a challenge in solid-state chemistry. Here, we report the hydrothermal crystal growth of a new copper tellurite sulfate, Cu 3 (TeO 4 )(SO 4 )•H 2 O, a promising alternative to layered perovskites. The orthorhombic phase (space group Pnma) is made of corrugated layers of corner-sharing CuO 4 square-planar units that are edge-shared with TeO 4 units. The layers are linked by slabs of corner-sharing CuO 4 and SO 4 . Using both the bond valence sum analysis and magnetization data, we find purely Cu 2+ ions within the layers but a mixed valence of Cu 2+ /Cu + between the layers. Cu 3 (TeO 4 )(SO 4 )•H 2 O undergoes an antiferromagnetic transition at T N = 67 K marked by a peak in the magnetic susceptibility. Upon further cooling, a spin-canting transition occurs at T* = 12 K, evidenced by a kink in the heat capacity. The spin-canting transition is explained on the basis of a J 1 −J 2 model of magnetic interactions, which is consistent with the slightly different in-plane superexchange paths. We present Cu 3 (TeO 4 )(SO 4 )•H 2 O as a promising platform for the future doping and strain experiments that could tune the Mott insulating ground state into superconducting or spin liquid states.

The Kagome lattice is an important fundamental structure in condensed matter physics for investigating the interplay of electron correlation, topology, and frustrated magnetism. Recent work on Kagome metals in the AV 3 Sb 5 (A = K, Rb, and Cs) family has shown a multitude of correlation-driven distortions, including symmetry breaking charge density waves and nematic superconductivity at low temperatures. Here, we study the new Kagome metal Yb 0.5 Co 3 Ge 3 and find a temperature-dependent kink in the resistivity that is highly similar to the AV 3 Sb 5 behavior and is commensurate with an in-plane structural distortion of the Co Kagome lattice along with a doubling of the c-axis. The symmetry is lower below the transition temperature, with a breaking the in-plane mirror planes and C 6 rotation, while gaining a screw axis along the c-direction. At very low temperatures, anisotropic negative magnetoresistance is observed, which may be related to anisotropic magnetism. This raises questions about the types of the distortions in Kagome nets and their resulting physical properties including superconductivity and magnetism.