Carrier induced ferromagnetism in diluted local-moment systems

Details Carrier induced ferromagnetism in diluted local-moment systems Carrier induced ferromagnetism in diluted local-moment systems

2006-12-24

arxiv.org/abs/cond-mat/0612611v1

Physics

Condensed Matter

Disordered Systems and Neural Networks

11 pages, 5 figures

Scientific paper

10.1103/PhysRevB.75.024426

The electronic and magnetic properties of concentrated and diluted ferromagnetic semiconductors are investigated by using the Kondo lattice model, which describes an interband exchange coupling between itinerant conduction electrons and localized magnetic moments. In our calculations, the electronic problem and the local magnetic problem are solved separately. For the electronic part an interpolating self-energy approach together with a coherent potential approximation (CPA) treatment of a dynamical alloy analogy is used to calculate temperature-dependent quasiparticle densities of states and the electronic self-energy of the diluted local-moment system. For constructing the magnetic phase diagram we use a modified RKKY theory by mapping the interband exchange to an effective Heisenberg model. The exchange integrals appear as functionals of the diluted electronic self-energy being therefore temperature- and carrier-concentration-dependent and covering RKKY as well as double exchange behavior. The disorder of the localized moments in the effective Heisenberg model is solved by a generalized locator CPA approach. The main results are: 1) extremely low carrier concentrations are sufficient to induce ferromagnetism; 2) the Curie temperature exhibits a strikingly non-monotonic behavior as a function of carrier concentration with a distinct maximum; 3) $T_C$ curves break down at critical $n/x$ due to antiferromagnetic correlations and 4) the dilution always lowers $T_C$ but broadens the ferromagnetic region with respect to carrier concentration.

Affiliated with

Also associated with

No associations

Rating

Carrier induced ferromagnetism in diluted local-moment systems does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Carrier induced ferromagnetism in diluted local-moment systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Carrier induced ferromagnetism in diluted local-moment systems will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-311041