Two new lanthanide-based 3D metal-organic frameworks (MOFs), {[Ln(L)(Ox)(HO)]·xHO} [Ln = Gd and x = 3 (1) and Dy and x = 1.5 (2); HL = mucic acid; OxH = oxalic acid] showing interesting magnetic properties and channel-mediated proton conduction behavior, are presented here. Single-crystal X-ray structure analysis shows that, in complex 1, the overall structure originates from the mucate-bridged gadolinium-based rectangular metallocycles. The packing view reveals the presence the two types of hydrophilic 1D channels filled with lattice water molecules, which are strongly hydrogen-bonded with coordinated water along the a and b axes, whereas for complex 2, the 3D framework originates from a carboxylate-bridged dysprosium-based criss-cross-type secondary building block. Magnetic studies reveal that 1 exhibits a significant magnetic entropy change (-ΔS) of 30.6 J kg K for ΔH= 7 T at 3 K. Our electronic structure calculations under the framework of density functional theory reveal that exchange interactions between Gd ions are weak and of the antiferromagnetic type. Complex 2 shows field-induced single-molecule-magnetic behavior. Impedance analysis shows that the proton conductivity of both complexes reaches up to the maximum value of 4.7 × 10 S cm for 1 and 9.06 × 10 S cm for 2 at high temperature (>75 °C) and relative humidity (RH; 95%). The Monte Carlo simulations confirm the exact location of the adsorbed water molecules in the framework after humidification (RH = 95%) for 1. Further, the results from computational simulation also reveal that the presence of a more dense arrangement of adsorbed water molecules through hydrogen bonding in a particular type of channel (along the a axis) contributes more to the proton migration compared to the other channel (along the b axis) in the framework.

Meticulous surface engineering of layered structures toward new functionalities is a demanding challenge to the scientific community.Here, we introduce defects on varied MoS 2 surfaces by suitable doping of nitrogen atoms in a sulfur-rich reaction environment, resulting in stable and scalable phase conversion. The experimental characterizations along with the theoretical calculations within the framework of density functional theory establish the impact of nitrogen doping on stabilization of defects and reconstruction of the 2H to 1T phase. The as-synthesized MoS 2 samples exhibit excellent dye removal capacity in the dark, facilitated by a synergistic effect of reactive oxygen species (ROS) generation and adsorption. Positron annihilation spectroscopy and electron paramagnetic resonance studies substantiate the role of defects and associated sulfur vacancies toward ROS generation in the dark. Further, on the basis of its ample ROS generation in the dark and in the light, the commendable antimicrobial activity of the prepared MoS 2 samples against fungal pathogen Alternaria alternata has been demonstrated. Thus, the present study opens up a futuristic avenue to develop newer functional materials through defect engineering by suitable dopants toward superior performances in environment issues.

The chain-like system Ba(3)Cu(3)Sc(4)O(12) has potentially interesting magnetic properties due to the presence of Cu(2+) and a structure-suggested low dimensionality. We present magnetization M versus magnetic field H and temperature T, T- and H-dependent heat-capacity C(p), (45)Sc nuclear magnetic resonance (NMR), muon spin rotation (μSR), neutron diffraction measurements and electronic structure calculations for Ba(3)Cu(3)Sc(4)O(12). The onset of magnetic long-range antiferromagnetic (AF) order at T(N) ∼ 16 K is consistently evidenced from the whole gamut of our data. A significant sensitivity of T(N) to the applied magnetic field H (T(N) ∼ 0 K for H = 70 kOe) is also reported. Coupled with a ferromagnetic Curie-Weiss temperature (θ(CW) ∼ 65 K) in the susceptibility (from a 100 to 300 K fit), it is indicative of competing ferromagnetic and antiferromagnetic interactions. These indications are corroborated by our density functional theory based electronic structure calculations, where we find the presence of significant ferromagnetic couplings between some copper ions whereas AF couplings were present between some others. Our experimental data, backed by our theoretical calculations, rule out the one-dimensional magnetic behavior suggested by the structure and the observed long-range order is due to the presence of non-negligible magnetic interactions between adjacent as well as next-nearest chains.

This work presents the emergence of superconductivity in Re substituted topological Weyl semimetal MoTe2. Re substitution for Mo sites lead to a sizable enhancement in the superconducting transition temperature (Tc). A record high Tc at ambient pressure in a 1T -MoTe2 (room temperature structure) related sample is observed for the Mo0.7Re0.3Te2 composition (Tc = 4.1 K, in comparison MoTe2, shows a Tc of 0.1 K). The experimental and theoretical studies indicate that Re substitution is doping electrons and facilitates the emergence of superconductivity by enhancing the electronphonon coupling and density of states at the Fermi level. Our findings, therefore, open a new way to further manipulate and enhance the superconducting state together with the topological states in 2D van der Waals materials.

We have synthesized polycrystalline and single crystal samples of PbCu 3 TeO 7 and studied its properties via magnetic susceptibility χ(T ) and heat-capacity C p (T ) measurements and also electronic structure calculations. Whereas the crystal structure is suggestive of the presence of a quasi-2D network of Cu 2+(S = 1/2) buckled staircase Kagome layers, the χ(T ) data show magnetic anisotropy and three magnetic anomalies at temperatures, T N 1 ∼ 36 K, T N 2 ∼ 25 K, T N 3 ∼ 17 K, respectively. The χ(T ) data follow the Curie-Weiss law above 200 K and a Curie-Weiss temperature θ CW ∼ −150 K is obtained. The data deviate from the simple Curie-Weiss law below 200 K, which is well above T N 1 , suggesting the presence of competing magnetic interactions. The magnetic anomaly at T N 3 appears to be of first-order from magnetization measurements, although our heat-capacity C p (T ) results do not display any anomaly at T N 3 . The hopping integrals obtained from our electronic structure calculations suggest the presence of significant intra-Kagome (next-nearest neighbor and diagonal) and inter-Kagome couplings. These couplings take the PbCu 3 TeO 7 system away from a disordered ground state and lead to long-range order, in contrast to what might be expected for an ideal (isotropic) 2D Kagome system.

Using first principles density functional calculations, we study the electronic structure of the low-dimensional multiferroic compound FeTe2O5Br to investigate the origin of the magnetoelectric (ME) effect and the role of Te ions in this system. We find that without magnetism even in the presence of Te-5s lone pairs, the system remains centrosymmetric due to the antipolar orientation of the lone pairs. Our study shows that the exchange striction within the Fe tetramers as well as between them is responsible for the ME effect in FeTe2O5Br. We also find that the Te 4+ ions play an important role in the inter-tetramer exchange striction as well as contribute to the electric polarization in FeTe2O5Br, once the polarization is triggered by the magnetic ordering.

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