Exchange interactions and Tc in rhenium doped silicon: DFT, DFT+U and Monte Carlo calculations
arXiv:1207.3059 · doi:10.1088/0953-8984/24/12/126002
Abstract
Interactions between rhenium impurities in silicon are investigated by means of the density functional theory (DFT) and the DFT+U scheme. All couplings between impurities are ferromagnetic except the Re-Re dimers which in the DFT method are nonmagnetic, due to formation of the chemical bond supported by substantial relaxation of the geometry. The critical temperature is calculated by means of classical Monte Carlo (MC) simulations with the Heisenberg hamiltonian. The uniform ferromagnetic phase is obtained with the DFT exchange interactions at room temperature for the impurities concentration of 7%. With the DFT+U exchange interactions, the ferromagnetic clusters form above room temperature in MC samples containing only 3% Re.
arXiv comment7 pages, 2 figures, 4 tables
References in corpus (8)
- Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
- A linear response approach to the calculation of the effective interaction parameters in the LDA+U method
- Ferromagnetism in semiconductors and oxides: prospects from a ten years' perspective
- Polaron percolation in diluted magnetic semiconductors
- Ferromagnetic semiconductors
- Improving the convergence of defect calculations in supercells - an ab initio study of the neutral silicon vacancy
- Aggregation and magnetism of Cr, Mn, and Fe cations in GaN
- The Fe-Mg interplay and the effect of deposition mode in (Ga,Fe)N doped with Mg