Single magnetic atoms absorbed on an atomically thin layer represent the ultimate limit of bit miniaturization for data storage. To approach the limit, a critical step is to find an appropriate material system with high chemical stability and large magnetic anisotropic energy. Here, on the basis of first-principles calculations and the spin-orbit coupling theory, it is elucidated that the transition-metal Mn and Fe atoms absorbed on disulfur vacancies of MoS2 monolayers are very promising candidates. It is analysed that these absorption systems are of not only high chemical stabilities but also much enhanced magnetic anisotropies and particularly the easy magnetization axis is changed from the in-plane one for Mn to the out-of-plane one for Fe by a symmetry-lowering Jahn-Teller distortion. The results point out a promising direction to achieve the ultimate goal of single adatomic magnets with utilizing the defective atomically thin layers.

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Novel capacitive-type humidity sensors with ultrahigh sensitivity based on graphene oxide (GO) combined with Ag nanoparticles (AgNPs) in different concentrations are reported in this study.

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Spin-polarized electronic structures of VAlON centers consisting of an aluminum vacancy and a substitutional oxygen in AlN with different charge states are studied by first-principles calculations. It is observed that a paramagnetic neutral VAlON center is stable in p-type AlN. The defect center possesses a triplet ground state and a spin-conserved excited state with rather low excitation energy and its spin coherence time is in an order of second at T = 0 estimated by using a mean-field-based scheme. The results indicate that the neutral VAlON center is a promising candidate for spin coherent manipulation and qubit operation.