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We have performed the first-principles calculations on the structural, electronic, and magnetic properties of 3d transition-metal™ (Cr, Mn, Fe, Co, and Ni) atoms doped 2D GaN nanosheet. The results show that 3d TM atom substituting one Ga leads to a structural reconstruction around the 3d TM impurity compared to the pristine GaN nanosheet. The doping of TM atom can induce magnetic moments, which are mainly located on the 3d TM atom and its nearest-neighbor N atoms. It is found that Mn- and Ni-doped GaN nanosheet with 100% spin polarization characters seem to be good candidates for spintronic applications. When two Ga atoms are substituted by two TM dopants, the ferromagnetic (FM) ordering becomes energetically more favorable for Cr-, Mn-, and Ni-doped GaN nanosheet with different distances of two TM atoms. On the contrary, the antiferromagnetic (AFM) ordering is energetically more favorable for Fe-doped GaN nanosheet. In addition, our GGA + U calculations show the similar results with GGA calculations. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We have performed the first-principles calculations on the structural, electronic, and magnetic properties of zigzag GaN nanoribbon (ZGaNNR) with period vacancy located at different sites across the ribbon width. The results show that, the formation of the N-vacancy is easier than that of the Ga-vacancy at each equivalent geometrical site and both of them are endothermic. An inward relaxation of the three nearest Ga atoms around a N-vacancy occurs, while for the three nearest-neighbor N atoms around the Ga-vacancy, an outward relaxation occurs. Except for a typical nonedge N-vacancy, the N-, or Ga-vacancies at other sites induce magnetic moment and spin polarization implying such vacancy-defective ZGaNNRs can be useful in spintronics and nanomagnets. The magnetic moment of the N-vacancy is dependent on defect sites, while for the Ga-vacancy, it is less dependent on the defect sites. The net magnetic moment of the vacancy defective 8-ZGaNNR is mainly contributed by the atoms around a vacancy. [ABSTRACT FROM AUTHOR]

Abstract: We present a systemic study of the structural, electronic and magnetic properties of Ni n nanowires (n =5, 9, 13) encapsulated in gallium nitride nanotubes (GaNNTs) using the first-principles calculations. We find that the initial shapes (quadratic–prismatic Ni nanowire and cylindrical (8,8) GaNNT) are preserved without any visible changes for the Ni5@(8,8) and Ni9@(8,8) systems, while for the Ni13@(8,8) system not only a quadraticlike cross-section shape is formed for nanotube but also an anticlockwise rotation about common axis is taken place for nanotube with respect to the nanowire. For both the free-standing Ni n nanowires and Ni n @(8,8) systems, the magnetic moment increases with decreasing the number n of the Ni atoms in per unit cell and increases as going from the core Ni atom to the outermost shell Ni atom for certain n. Both the total density of states (DOS) and charge density analyses show that the spin polarization and the magnetic moment of Ni n @(8,8) systems come solely from the Ni nanowires. Not much decreasing in the spin polarization and the magnetic moment for the Ni n @(8,8) systems with respect to the corresponding free-standing Ni n nanowires imply the Ni n @(8,8) systems can be applied to the circuits that demand preferential transport of electrons with a specific spin. [ABSTRACT FROM AUTHOR]

Abstract: We have performed first-principles calculations on the structural, electronic and magnetic properties of seven different 3d transition-metal (TM) impurity (V, Cr, Mn, Fe, Co, Ni and Cu) doped armchair (5,0) and zigzag (8,0) gallium nitride nanotubes (GaNNTs). The results show that there is distortion around 3d TM impurities with respect to the pristine GaNNTs for 3d TM-doped (5,5) and (8,0) GaNNTs. The change of total magnetic moment follows Hund’s rule for 3d TM-doped (5,5) and (8,0) GaNNTs, respectively. The total density of states (DOS) indicates that Cr-, Mn-, Fe- and Ni-doped (5,5) GaNNTs as well as Cr-, Mn-, Ni- and Cu-doped (8,0) GaNNTs are all half-metals with 100% spin polarization. The study suggests that such TM-doped nanotubes may be useful in spintronics and nanomagnets. [Copyright &y& Elsevier]

CrI 3 monolayer is a two-dimensional (2D) ferromagnetic (FM) semiconductor materials with broad application prospects in the field of spintronics due to its magnetic semiconductor feature and unique 2D structure. In this work, we employ first-principles calculations based on density functional theory to investigate the electronic structure and magnetic properties of CrI 3 monolayer doped with rare earth (RE) metal atoms (RE = Sc, Y, La, Ce, Pr, Nd, Pm , Eu, Gd, Tm, and Lu). The results demonstrate that doping with RE atoms enables the control of total magnetic moments and a significantly enhancement of the Curie temperature of CrI 3 monolayer. Especially, the Curie temperature of CrGdI 6 monolayer reaches 347.58 K, which could be a promising candidate for realizing room temperature ferromagnetism. Furthermore, by applying strain and electric field, the CrREI 6 monolayers exhibit metal, half-metal and spin gapless semiconductor properties. These findings not only provide valuable insights into the manipulation of electronic structure and magnetic properties in CrI 3 monolayer but also establish RE doped CrI 3 monolayer as a promising material for spintronic devices. [Display omitted] • The electronic structure and magnetic properties of RE doping CrI 3 monolayer are studied by DFT-D2 method. • The RE doping can regulate the total magnetic moment and electronic structure of the CrREI 6 monolayers. • The T c of CrGdI 6 monolayer reaches 347.58 K, which is a candidate material for realizing room temperature ferromagnetism. • The CrREI 6 monolayers show metal, half-metal and spin gapless semiconductor properties by applying strain and electric field. [ABSTRACT FROM AUTHOR]