Volume 8 Issue 3, March 2016

Two parallel semiconducting TiO₂ zones, anatase and rutile, are made to have lower and higher electron densities, respectively, and form periodically organized junctions through anatase–rutile-phase transition in selective areas by laser irradiation on the titanium bone implants. The periodic junctions result in the formation of a periodic microscale electric field (MEF), built-in on the implants, which in turn efficiently induces and promotes osteogenesis.

The effects of structural relaxation (SR) on the electronic state of oxygen vacancies (V_O s) in amorphous oxide semiconductors is investigated. Without redox reactions, the concentration of V_O s in the shallow-donor state (N_DS) increases about 10³ times with increases in the annealing temperature from 300 to 450 °C. The reduction in the free volume size and transformation of V_O s in either deep-donor or electron-trap states into the shallow-donor state during SR is the primary mechanism responsible for the increase in N_DS.

A new surface-directed crystallization mechanism enabled by the chemical and structural inhomogeneity of the glass substrate through self-limited nanocrystallization of glassy phase was proposed and demonstrated. Benefiting from the intricate interplays between nanoscale force and heterogeneous surface, the strategy offers new opportunities in the large-scale development of various metastable crystallization products and also serves practical purpose.

Trimodally porous SnO₂ nanospheres with pore sizes of 3, 20 and 100 nm were prepared with facile one-pot spray pyrolysis and their potential for extremely sensitive ethanol detector was demonstrated. The precise control over, as well as the tuning of, multimodal pores in metal oxide nanostructures provides a new and general strategy for enhancing the performance of nanomaterials for various energy and environmental applications.

Naturally occurring and magnetically induced optical activities (the Faraday effect) have contributed to our understanding of molecular electronic states, and have also had various applications in photonics. It has been generally considered that the Faraday effect is not affected by natural optical activity originating from chirality. Herein we describe for the first time a relationship between the Faraday rotation angles and chirality in a chiral lanthanide cluster. This finding provides new insights into the design of next-generation molecular Faraday materials and may lead to the development of a novel area of study within the field of chiral science.

A minute presence of silver nanoclusters in a MoS₂ nanosheet–graphene composite was found to significantly increase the reversibility of Li⁺ storage in the composite through Li⁺ association, pillaring of graphene and the immobilization of S species.

A hydrophobic porous coordination polymer (PCP) has been synthesized and its growth throughout the graphene oxide (GO)-modified sponge yields a macroscopic PCP@GO@sponge sorbent, which repels water and exhibits superior adsorption for diverse oils. Remarkably, the sorbent is further assembled with tubes and a self-priming pump to build a model apparatus that can afford consecutive and efficient oil recovery from water.

To realize practical application, the attenuation of spin waves because of boundary scattering and multimode dispersion in magnonic waveguides must be greatly reduced. Up to now, there have been not good solutions to this problem. Here, we propose and demonstrate by micromagnetic simulations to use the longitudinal chiral domain wall imprinted into a waveguide with the interfacial Dzyaloshinskii–Moriya interaction (DMI) to introduce a deep potential well and guide spin waves forming an ultra narrow internal spin-wave channel (~10 nm). Spin waves along this channel can prevent scattering arising from boundary roughness and multimode coexistence and thus should exhibit reduced attenuation and enhanced coherence, which is highly desired in building real spin-wave devices. Moreover, we show that the spin-wave transmission in this waveguide with the DMI can be switched on and off at the frequencies lower than a threshold frequency f₂ by changing the static domain state. This property is explored to construct logical NAND gate by connecting two logical NOT gates in parallel.

It can be found that the Mn/Si ratio is a crucial factor affecting the morphology of the as-obtained products. The pristine Si nanoparticles are sphere-like particles of ~100 nm in diameter. When the Mn/Si molar ratio is 4:1, ultrafine MnCO₃ nanowires less than 10 nm in diameter are obtained. The MnO@C nanowires were synthesized via polymerization–pyrolysis steps, and the excellent high-rate performance and stability of the MnO@C nanowires used as an anode in the lithium-ion battery are attributed to the unique interconnected nanostructure.

Our study reveals the first experimental evidence that charge transport can be tuned from partially to fully coherent. We used pentacene, a soft organic material, to measure transport properties depending on temperature and pressure. Under ambient conditions, charge transport was only partially coherent. At 1 GPa and below 220 K fully coherent charge transport emerged. Microscopically, we find that the thermal fluctuations are reduced so that the charge carriers start moving around freely leading to a coherent charge transport.

Formation of a strained Si membrane with oxidation-induced residual strain by releasing a host Si substrate of a silicon-on-insulator (SOI) wafer is demonstrated. To do this, we construct suspended Si/SiO₂ structures and induce over 0.5% tensile strain on the top Si membrane. The fabricated thin-film transistor (TFTs) with strained Si channels are transferred on plastics using a roll-based transfer technique, and they exhibit a mobility enhancement factor of 1.2–1.4 in comparison with an unstrained Si TFT.

A novel strategy is demonstrated to produce silicon nanosheets on a large scale through the simultaneous molten-salt-induced exfoliation and chemical reduction of natural clay. The thus-synthesized silicon nanosheets have a high surface area, are ultrathin (~5 nm), and contain mesoporous structures derived from the oxygen vacancies in the clay. These advantages make the nanosheets a highly suited photocatalyst with an exceptionally high activity (723 μmol H₂ per h per g Si) for the generation of hydrogen from a water–methanol mixture.

The facile conduction of alkali ions in a crystal host is of crucial importance in rechargeable alkali-ion batteries. This review provides a comprehensive survey of the various computational approaches, such as transition state, molecular dynamics and Monte Carlo methods, to study solid-state alkali diffusion, discusses how these methods have provided useful insights into the design of crystalline materials that form the main components of a rechargeable alkali-ion battery, namely the electrodes, superionic conductor solid electrolytes and their interfaces, and provides our perspective on the future challenges and directions in computational alkali diffusion studies.