Half‐Metallicity in Single‐Layered Manganese Dioxide Nanosheets by Defect Engineering

Abstract

Defect engineering is considered as one of the most efficient strategies to regulate the electronic structure of materials and involves the manipulation of the types, concentrations, and spatial distributions of defects, resulting in unprecedented properties. It is shown that a single-layered MnO 2 nanosheet with vacancies is a robust half-metal, which was confirmed by theoretical calculations, whereas vacancyfree single-layered MnO 2 is a typical semiconductor. The halfmetallicity of the single-layered MnO 2 nanosheet can be observed for a wide range of vacancy concentrations and even in the co-presence of Mn and O vacancies. This work enables the development of half-metals by defect engineering of well-established low-dimensional materials, which may be used for the design of next-generation paper-like spintronics.Half-metals, with a metallic nature for one spin and an insulating/semiconducting nature for the opposite spin, are considered as ideal materials for applications in spintronics, because their carriers are theoretically 100 % spin-polarized. [1,2] To date, various half-metals have been reported, which are mainly based on bulk oxides, Heusler alloys, or perovskites, whereas attention has rarely been paid to the half-metallicity in low-dimensional materials.

Superior Electrical Conductivity in Hydrogenated Layered Ternary Chalcogenide Nanosheets for Flexible All‐Solid‐State Supercapacitors

“…[9,15] Although many theoretical studies have been carried out on how to control the electronic structure in 2D crystals,experimental realization is difficult as harsh conditions are required, and the underlying principles are still unclear. [16,17] Due to their rich electronic structures and diverse chemical compositions,t he layered transition-metal chalcogenides offer ideal platforms to search for highly conductive 2D crystals by electronic structural control, and to understand their mechanisms.C urrently,r esearch interests on layered TMCs were expanded from the binary compounds to ternary or multiple-valued counterparts,w ho show richer electronic structures. [18][19][20] Herein, we investigate the ternary chalcogenides with formula of Cu 2 MX 4 (M = Mo,W ;X= S, Se), which possess al ayered structure with weak van der Waals forces between the layers.…”

Nanofabrication strategies for advanced electrode materials

“…Nowadays, energy-, envirmental-and time-cost are needed to consider during the choice of synthesis strategies. Hydrothermal, electrodeposition, microwave and sol-gel methods have been considered as greener and economic methods [59,60]. However, for the selecting fast nanofabrication method, combustion synthsis is the first choice, which also shows additional bonuses: (I) the combustion exothermic reaction provides the required reaction energy, once ignited without the need of external energy input, (II) the reaction time is short (usually seconds), (III) only needing simple equipment and environmentally friendly chemicals [61,62].…”

Tuning the tunneling magnetoresistance by using fluorinated graphene in graphene based magnetic junctions

“…The above requirements can be fulfilled by using half-metallic ferromagnets (HMF) as electrodes with 100 % spin-polarization. [37][38][39] Due to 100 % spin-polarization in HMF, negligible current is obtained in antiparallel configuration (APC) as it allows only one type of spin to propagate through the channel and blocks other type of spin. This translates into high TMR values.…”