A two-dimensional ferromagnetic semiconductor Cr2Ge2Te6 (CGT) was recently found to possess extraordinary characteristics and has great potential in the emerging field of spintronics. Using first-principles calculations, we examined the stabilities of this layered system by studying the cleavage energies and phonon dispersion. The ferromagnetic ground state has an in-plane spin polarization and bandgaps of about 0.26 eV by Perdew-Burke-Ernzerhof-van der Waals and 0.91 eV by the Heyd-Scuseria-Ernzerhof functional. Furthermore, we employed strain engineering and an external electric field to control the electronic and magnetic properties. In addition, we studied the magnetic anisotropy energy as well as its modulation under the electric field. We predict the CGT monolayer to be the easy plane ferromagnet, and the perpendicular electric field could affect the ferromagnetic stability along different directions. Our obtained results provide guidance for the potential applications of monolayer CGT for magnetic nanodevices, spintronic, and straintronic applications.

Designing an electric-field controlled Rashba spin FET on two-dimensional GeTe.

The magnetic properties of Cr2Ge2Te6, an important two-dimensional ferromagnetic material, are investigated at the molecular level by constructing and solving realistic models extracted from first-principles electronic structure calculations.

Nitrogen-doped carbon quantum dots (N-CQDs) with citric acid and ethylenediamine as raw materials were synthesized by an efficient one-step strategy. The N-CQDs showed a special property that the fluorescence was quenched by Fe. The quenched fluorescence of N-CQDs could be recovered by glutathione (GSH). Therefore, a "signal-on" fluorescent sensor was developed to detect GSH. The fluorescent sensor could favorably avoid the interference of ascorbic acid, dopamine, glucose, oxidized glutathione, and other amino acids in the detecting process of GSH. The proposed sensor showed a great feature that GSH can be accurately detected in the range from 0.001 to 0.1 mol/L and can be applied to detect GSH in the human serum. Therefore, the proposed method has a promising application for monitoring the blood drug concentration of GSH in clinical studies.

The perturbation proceduressuggested in the spin-orbit (so) couplingmechanism contibuting to the %-state splitting are examined in detail and round to be all correct for tetragonal symmetry, on the basis of a diagonalization calculation. The BlumMrbach procedure is most appropriate. The sixth-order perturbation must be taken into account in strong fields for the procedure proposed by Watanabe and developed by Yu and Zhao, and the expression is given here Among the various mechanisms which contribute to the zero-field splitting of %-state ions, the spin-orbit (SO) coupling mechanism has been found to be most important for many substances and thus has become the subject of many recent papers [I-51. There areat least three altemative approaches to the perturbation procedure [ 11. Among them the well known and extensively used Blume-Orbach procedures [6, 71 (called so-I hereafter) was recently indicated as not appropriate for rhombic symmetry [3]. The procedure proposed by Watanabe [8] and developed by Yu and Zhao [2] (denoted

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