Density functional study on ferromagnetism in nitrogen-doped anatase TiO2

Abstract

We report first principles calculations on the magnetism and electronic structures for nitrogen-doped anatase TiO2 (N:TiO2). Our calculations indicate that magnetic state is the ground state for N:TiO2 systems. An isolated N atom produces a total magnetic moment of 1.00μB and introduces spin-polarized 2p states in the band gap. The origin of the magnetic moments is the holes in N 2p π band of the N dopant. Several doping configurations studied suggest the existence of ferromagnetic coupling between N dopants. The ferromagnetism in N:TiO2 can be attributed to the hole-mediated double exchange through the strong p-p interaction between N and O.

Possible ferromagnetism in Li, Na and K-doped AlN: A first-principle study

“…This outward relaxation can be attributed to the Coulomb repulsion effect and the larger ionic radius of the doping atom than replaced host atom. For Al 35 LiN 36 , Al 35 NaN 36 and Al 35 KN 36 , the calculated total energy of spin polarized state is lower than that of non-spin polarized state by about 213, 251 and 272 meV, respectively, which indicate that all of Li, Na and K doped AlN materials favor the spin polarized state. All of the calculated magnetic moments for three doped systems Al 35 XN 36 (X¼Li, Na and K) are 2.0 m B .…”

First-principles study on ferromagnetism in nitrogen-doped CdO

“…While in N-doped ZnO [15], when the two N atoms are separated by 6.136 Å, the energy of FM states is 22 MeV lower than that of the corresponding AFM one. This implies the long-range RT ferromagnetism for N:CdO is quite feasible, which makes N:CdO system superior to the previous observed FM materials [11][12][13][14][15][16].…”

“…These extrinsic magnetic behaviors are undesirable for practical applications and strongly dependent on the preparation methods and conditions. Very recently, unexpected ferromagnetism in the non-magnetic elements doped DMSs [10][11][12][13][14][15][16] provide a new opportunity to search new spintronic materials. For instance, both N-doped ZnO and TiO 2 were found theoretically to be RT FM materials [11,12,15].…”

Ferromagnetism induced by intrinsic defects and carbon substitution in single-walled ZnO nanotube

“…Most of ab initio calculations demonstrate that cation vacancies are responsible for the magnetic moments in undoped oxides such as HfO 2 , TiO 2 , ZnO, SnO 2 , ZrO 2 and MgO [8][9][10][11][12][13][14][15][16]. Ferromagnetism could also be produced by doping non-magnetic sp elements such as C, N, Mg and Al in oxides, nitrides and sulfides [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. The presence of these sp impurities could transform the non-magnetic compounds into magnetic systems, and the magnetization originates mainly from the spin-splitting of (C, N, O, S) 2p states.…”