2004/08/09 by Jinming Xu, J. L. Xu, Mark van Schilfgaarde +3
Materials Science · Physics and Astronomy · #Condensed matter physics #Coupling (piping) #Electronic structure #Energy (signal processing) #Ferromagnetism #Heisenberg model #Impurity #Local-density approximation #Magnetic and transport properties of perovskites and related materials #Magnetic semiconductor #Materials science #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Spin (aerodynamics) #Thermodynamics #ZnO doping and properties #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevlett.94.097201
10 pages, 3 figures
arxiv created 2004/08/09 · openalex publication_date 2005/03/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present calculations of magnetic exchange interactions and critical temperature Tc in Ga_1\ensuremath-xMnxAs, Ga_1\ensuremath-xCrxAs, and Ga_1\ensuremath-xCrxN. The local spin-density approximation is combined with a linear-response technique to map the magnetic energy onto a Heisenberg Hamiltonion, but no significant further approximations are made. We show the following: (i) configurational disorder results in large dispersions in the pairwise exchange interactions; (ii) the disorder strongly reduces Tc; (iii) clustering in the magnetic atoms, whose tendency is predicted from total-energy considerations, further reduces Tc, while ordering the dopants on a lattice increases it. With all the factors taken into account, Tc is reasonably predicted by the local spin-density approximation in Mn:GaAs without the need to invoke compensation by donor impurities.