Pressure Driven Fractionalization of Ionic Spins Results in Cupratelike High-T_{c} Superconductivity in La_{3}Ni_{2}O_{7}.

Beyond 14 GPa of pressure, bilayered La_{3}Ni_{2}O_{7} was recently found to develop strong superconductivity above the liquid nitrogen boiling temperature. An immediate essential question is the pressure-induced qualitative change of electronic structure that enables the exciting high-temperature superconductivity. We investigate this timely question via a numerical multiscale derivation of effective many-body physics. At the atomic scale, we first clarify that the system has a strong charge transfer nature with itinerant carriers residing mainly in the in-plane oxygen between spin-1 Ni^{2+} ions. We then elucidate in electron-volt scale and sub-electron-volt scale the key physical effect of the applied pressure: it induces a cupratelike electronic structure via fractionalizing the Ni ionic spin from 1 to 1/2. This suggests a high-temperature superconductivity in La_{3}Ni_{2}O_{7} with microscopic mechanism and (d-wave) symmetry similar to that in the cuprates.

Space-confined synthesis of monolayer molybdenum disulfide using tetrathiomolybdate intercalated layered double hydroxide as precursor.

Monolayer molybdenum disulfide (M-MoS2) nanosheets (NSs) have attracted tremendous attention owing to their extraordinary properties and extensive potential applications. However, the large-scale and cost-effective fabrication of uniform M-MoS2 NSs remains challenging. Herein, a novel space-confined synthesis strategy was developed for M-MoS2 NSs, using the interlayer spaces of layered double hydroxides (LDHs) as nanoreactors. The 2H-phase M-MoS2 NSs dispersed in water were obtained with a high production yield of ∼98.7%, a quite high monolayer ratio of ∼95%, a homogenous lateral size of ∼89 nm, and a large monodispersed concentration of ∼0.41 g L-1. The so-obtained M-MoS2 exhibits excellent electrocatalytic activity towards the hydrogen evolution reaction compared with bulk MoS2. This work provides an effective route for large-scale fabrication of two-dimensional transition-metal dichalcogenide nanomaterials.