Ferromagnetism in Mo-doped TiO2 Rutile from Ab Initio Study

Abstract

First-principles calculations based on spin density functional theory (DFT) within the general gradient approximation (GGA) are performed to study the spin-resolved electronic properties of TiO 2 Rutile doped with 6.25 and 12.5% of Mo. The Mo impurity is found spin polarized and the calculated band structures suggest a 100% polarization of the conduction carriers. The local moment of Molybdenum is slightly dependent on its concentration. The Fermi level is shifted to the bottom of the conduction band with increasing concentration of Mo. This leads to the increase of states density, just above the Fermi level, and consequently the 4d orbitals are strongly hybridized with Ti 3d ones to form a d-nature conduction band, without impurity states in the in-gap region. The Mo-doped TiO 2 favors ferromagnetic ground state which can be explained in terms of p-d hybridization mechanism for 6.25% of Mo, this mechanism depends on the Mo concentration. This suggests that the Mo-doped TiO 2 is a promising dilute magnetic semiconductor and may find applications in the field of spintronics.

Universal features underlying the magnetism in diluted magnetic semiconductors

“…Analogous findings were also reported for GaN codoped with (Mn,Co) and (Cr,Mn) [32]; in Cr:TiO 2 and in Mn:GaAs following a p − d hopping interaction [33]; in TiO 2 [34][35][36] following a non-compensated n − p doping [34], or following the passivation of codopants (Mo,C) [37]. Less popular appear to be the investigations on the effect of doping/ codoping on magnetism in SnO 2 [35,38,39], Sn 3 N 4 [40,41], MoS 2 [42][43][44], ZnS [45][46][47] and CdS [48][49][50][51][52][53]; for these hosts the focus of the investigation is mainly limited to engineering of their band gap through TM-doping and their applications in catalysis.…”

Rare-earth-doped TiO2 rutile as a promising ferromagnetic alloy for visible light absorption in solar cells: first principle insights

“…Due to the overlapping of the impurity states with the conduction band in Sm-, Pm-, and Nd-doped TiO 2 materials, the underlying mechanism responsible for the ferromagnetism is the same as that mentioned in the study of the doped ZnO material with double impurities, Zn 1À2x Fe x Co x O 49 and Modoped TiO 2 rutile. 50 In fact, the oxidation states of the Sm-, Pm-, and Nd-, impurities in the host matrix are measured roughly from the carrier's occupancy in the 4f orbitals. Tables 1 and 2 show the PBEsol-calculated total and partial magnetic moments for both rare-earths concentration (x ¼ 0.625 and 0.125) for the FM spin congurations.…”

Origin of Ferromagnetism in Ru and N Codoped TiO2 Nanotubes: Experiments and Theory Investigations

“…Diluted magnetic oxide semiconductors (DMOSs) have been extensively studied because of the combined transport properties and magnetic properties, which are desirable for spintronic application [1]. The investigations mainly focus on metal doped and nonmetal doped TiO 2 , specially for transition metal doping which contains unpaired d electron configuration, such as Mo [2], Co [3], Fe [4], Mn [5], and V [6], and for nonmental elements doping, such as C [7], N [8,9], and S [10]. There are several models to explain the ferromagnetic origin, for example, Stoner-type model [11] and band coupling model [12].…”