Magnetic and Electronic Properties of Nitrogen-Doped Lanthanum Sesquioxide La2O3 as Predicted from First Principles

Abstract

Using the ab initio FLAPW-GGA method we examine the electronic and magnetic properties of nitrogen-doped nonmagnetic sesquioxide La 2 O 3 emphasizing the role of doping sites in the occurrence of d 0magnetism. We predict the magnetization of La 2 O 3 induced by nitrogen impurity in both octahedral and tetrahedral sites of the oxygen sublattice. The most interesting results are that (i) the total magnetic moments (about 1 μ B per supercells) are independent of the doping site, whereas (ii) the electronic spectra of these systems differ drastically: La 2 O 3 :N with six-fold coordinated nitrogen behaves as a narrow-band-gap magnetic semiconductor, whereas with four-fold coordinated nitrogen is predicted to be a magnetic half-metal. This effect is explained taking into account the differences in N-2p z ↓↑ versus N-2p x , y ↓↑ orbital splitting for various doping sites. Thus, the type of the doping site is one of the essential factors for designing of new d 0 -magnetic materials with promising properties.

First-principles study of the effect of oxygen vacancy and iridium doping on formaldehyde adsorption on the La2O3(001) surface

“…The interaction between ions and valence electrons was described by the projected additive wave (PAW) method, and the exchange-correlation potential between electrons was processed by the Perdew-Burke-Ernzerhof (PBE) functional of generalized gradient approximation (GGA). 29,32,33 Through testing, the plane wave truncation kinetic energy was set as 600 eV, the force was distributed to each atom, and the convergence value of the total system energy was less than 3.0 × 10 −3 eV nm −1 and 1.0 × 10 −5 eV per atom, respectively. The deviations of stress and displacement were less than 0.05 GPa and 1.0 × 10 −4 nm, respectively.…”

“…The result indicated that Sr-doped La 2 O 3 clusters had higher thermodynamic and kinetic activity due to the catalytic oxidative coupling of methane, wherein the formed Sr–O bond had stronger reactivity with methane and a lower energy barrier to overcome the reaction with methane than the La–O bond. Bannikov et al 29 reported that the bonding of the doped elements had a significant impact on the magnetic properties of La 2 O 3 . The nitrogen (N)-doped La 2 O 3 combined with six ligands had magnetic, narrow-band semiconductor characteristics.…”

Robustness and stability of half-metallic ferromagnetism in alkaline-earth metal mononitrides against doping and deformation

“…5 N impurities at anionic sites (oxygens) present a splitting of their p-bands and the majority-spin states are completely occupied while the minority-spin states are partially occupied leading to half-metallicity. [17][18][19][20][21][22] Experimental evidence for the occurrence of magnetism in N-doped MgO has been provided by Liu and collaborators. 23 An alternative way to half-metallic sp-electron ferromagnets is the growth of I/II-IV/V nanostructures in metastable lattice structures similar to the case of transition-metal pnictides and chalcogenides in the metastable zincblende structure.…”