Spin-Polarized Structural, Electronic, and Magnetic Properties of Diluted Magnetic Semiconductors Cd_1−xMn_xS and Cd_1−xMn_xSe in Zinc Blende Phase

Abstract

We studied the structural, spin-polarized electronic band structures, density of states, and magnetic properties of the diluted magnetic semiconductors (DMSs) Cd(1-x)Mn(x)S and Cd(1-x)Mn(x)Se in zinc blende phase (B3) with 25% Mn by using the ab initio method. The calculations were performed by using the full potential linearized augmented plane wave plus local orbitals (FP-L/APW+lo) method within the spin-polarized density functional theory and the local spin density approximation (LSDA). Calculated electronic band structures and the density of states of these DMSs are discussed in terms of the contribution of Mn 3d(5)4s(2), Cd 4d(10)5s(2), S 3s(2)3p(4), and Se 4s(2)4p(4) partial density of states and we also compute the local magnetic moments. We estimated the spin-exchange splitting energies, Delta(x)(d) and Delta(x)(p-d), produced by the Mn 3d states, and we found that the effective potential for the minority spin is more attractive than that for the majority spin. We determine the s-d exchange constant N(0)alpha and p-d exchange constant N(0)beta, which resembles a typical magneto-optical experiment. The calculated total magnetic moment is found to be 5.0020 and 5.00013 mu(B) for Cd(1-x)Mn(x)S and Cd(1-x)Mn(x)Se, respectively. These values indicate that every Mn impurity adds no hole carriers to the perfect CdS and CdSe crystals. Moreover, we found that p-d hybridization reduces the local magnetic moment of Mn from its free space charge value of 5.0micro(B) and produces small local magnetic moments on the nonmagnetic Cd and S sites.

Understanding of ferromagnetism in thiol capped Mn doped CdS nanocrystals

“…These materials exhibit both semiconducting as well as magnetic properties, which offer unprecedented opportunities for both optoelectronic 1-4 and spintronic 5,6 devices. Ferromagnetism in III-V class, DMS has been predicted initially by Dietl et al 7 and since then, several reports are published on the existence of roomtemperature ferromagnetism in both undoped 8 and doped [9][10][11] semiconductor nanoparticles.…”

First principle electronic structure calculations of ternary alloys Hg1−xMnxTe in zinc-blende structure

“…The II-VI diluted magnetic semiconductors [5][6][7][8] crystallize in zinc-blende (ZB) or wurtzite structure defined by the binary host crystal structure. The ternary nature of A II 1Àx Mn x B VI provides the possibility of tuning the lattice and band parameters by varying the composition of the material [9].…”

First-principles study of spin-polarized electronic band structures in ferromagnetic Zn1−xTMxS (TM=Fe, Co and Ni)

“…From the conduction and valence band edges the exchange constants can be calculated as given in Ref. [37] and the calculated values of N 0ą nd N 0ˇf or Zn 0.75 Fe 0.25 S, Zn 0.75 Co 0.25 S and Zn 0.75 Ni 0.25 S are displayed in Table 4. We find that N 0˛i s much smaller than N 0ˇ, which means that the interaction between the cation s and the TM d states at the conduction band minimum is much weaker than the p-d interaction at the valence band maximum; this result indicates ferromagnetic behavior of these materials.…”