On the reliability of recent Monte Carlo studies of dilute systems of localized spins interacting with itinerant carriers

Abstract

In this paper, we discuss magnetic properties of dilute systems of localized spins interacting with itinerant carriers. More precisely, we compare recent available Monte Carlo results with our two step approach (TSA) calculations. The TSA consists first on the determination of the magnetic couplings and then on a proper treatment of the resulting effective dilute Heisenberg Hamiltonian. We show important disagreement between the Monte Carlo results (in principle exact) and our TSA calculations. We analyze the origins and shed light on the reasons of those dissensions. In contrast to one could expect, we demonstrate that the available MC calculations suffer from severe numerical shortcomings. More precisely, (i) the finite size effects appear to be huge in dilute systems, (ii) the statistical sampling (disorder configurations) was far too small, and (iii) the determination of the Curie temperature was too rough. In addition, we provide new arguments to explain a recent disagreement between the Monte Carlo simulations and TSA for the model study of the well known III-V diluted magnetic semiconductor Ga${}_{1-x}$Mn${}_x$As. We hope that this work will motivate new systematic large scale Monte Carlo calculations.

11 figures, submitted to Phys. Rev

References in corpus (12)

• Model for vacancy-induced d${}^0$ ferromagnetism in oxide compounds
• Compensation, interstitial defects and ferromagnetism in diluted semiconductors
• Monte Carlo Study of Doping Change and Disorder Effect on Double Exchange Ferromagnetism
• Order N Monte Carlo Algorithm for Fermion Systems Coupled with Fluctuating Adiabatical Fields
• Effects of correlated disorder on the magnetism of double exchange systems
• Critical Temperatures of a Two-Band Model for Diluted Magnetic Semiconductors
• Large-Scale Monte Carlo Study of a Realistic Lattice Model for Ga_(1-x)Mn_xAs
• The Crossover from Impurity to Valence Band in Diluted Magnetic Semiconductors: The Role of the Coulomb Attraction by Acceptor
• Study of the One- and Two-Band Models for Colossal Magnetoresistive Manganites Using the Truncated Polynomial Expansion Method
• Superexchange induced canted ferromagnetism in dilute magnets
• Comment on the PRL "Large-Scale Monte Carlo Study of a Realistic Lattice Model for Ga_(1-x)Mn_xAs"
• Comparison between ab-initio and phenomenological modeling of the exchange couplings in diluted magnetic semiconductors: the case of $Z{n}_{1-x}C{r}_{x}Te$

Cited by in corpus (2)

• Carrier induced ferromagnetism in the insulating Mn doped III-V semiconductor InP
• Reconsidering the possibility of room temperature ferromagnetism in Mn doped Zirconium oxide