Dynamic-to-static switch of hydrogen bonds induces a metal-insulator transition in an organic-inorganic superlattice.

Hydrogen bonds profoundly influence the fundamental chemical, physical and biological properties of molecules and materials. Owing to their relatively weaker interactions compared to other chemical bonds, hydrogen bonds alone are generally insufficient to induce substantial changes in electrical properties, thus imposing severe constraints on their applications in related devices. Here we report a metal-insulator transition controlled by hydrogen bonds for an organic-inorganic (1,3-diaminopropane)SnSe superlattice that exhibits a colossal on-off ratio of 10 in electrical resistivity.

Disorder-Broadened Phase Boundary with Enhanced Amorphous Superconductivity in Pressurized InTe.

As an empirical tool in materials science and engineering, the iconic phase diagram owes its robustness and practicality to the topological characteristics rooted in the celebrated Gibbs phase law free variables (F) = components (C) - phases (P) + 2. When crossing the phase diagram boundary, the structure transition occurs abruptly, bringing about an instantaneous change in physical properties and limited controllability on the boundaries (F = 1). Here, the sharp phase boundary is expanded to an amorphous transition region (F = 2) by partially disrupting the long-range translational symmetry, leading to a sequential crystalline-amorphous-crystalline (CAC) transition in a pressurized InTe single crystal.

Superconductivity in an Orbital-Reoriented SnAs Square Lattice: A Case Study of Li Sn As and NaSnAs.

Searching for functional square lattices in layered superconductor systems offers an explicit clue to modify the electron behavior and find exotic properties. The trigonal SnAs structural units in SnAs-based systems are relatively conformable to distortion, which provides the possibility to achieve structurally topological transformation and higher superconducting transition temperatures. In the present work, the functional As square lattice was realized and activated in Li Sn As and NaSnAs through a topotactic structural transformation of trigonal SnAs to square SnAs under pressure, resulting in a record-high T among all synthesized SnAs-based compounds.

High Entropy van der Waals Materials.

By breaking the restrictions on traditional alloying strategy, the high entropy concept has promoted the exploration of the central area of phase space, thus broadening the horizon of alloy exploitation. This review highlights the marriage of the high entropy concept and van der Waals systems to form a new family of materials category, namely the high entropy van der Waals materials (HEX, HE = high entropy, X = anion clusters) and describes the current issues and next challenges. The design strategy for HEX has integrated the local feature (e.

Caging-Pnictogen-Induced Superconductivity in Skutterudites IrX (X = As, P).

Here, we report on a new kind of compound, XIrX (X = P, As), the first hole-doped skutterudites superconductor. We provide atomic-resolution images of the caging As atoms using scanning transmission electron microscopy (STEM). By inserting As atoms into the caged structure under a high pressure, superconductivity emerges with a maximum transition temperature () of 4.

High-Entropy van der Waals Materials Formed from Mixed Metal Dichalcogenides, Halides, and Phosphorus Trisulfides.

The charge, spin, and composition degrees of freedom in a high-entropy alloy endow it with tunable valence and spin states, infinite combinations, and excellent mechanical performance. Meanwhile, the stacking, interlayer, and angle degrees of freedom in a van der Waals material bring to it exceptional features and technological applications. Integration of these two distinct material categories while keeping their merits would be tempting.