Onset of ferromagnetism in low-doped GaMnAs

Abstract

We develop a quantitatively predictive theory for impurity-band ferromagnetism in the low-doping regime of GaMnAs and compare with experimental measurements of a series of samples whose compositions span the transition from paramagnetic insulating to ferromagnetic conducting behavior. The theoretical Curie temperatures depend sensitively on the local fluctuations in the Mn-hole binding energy, which originates from disorder in the Mn distribution as well as the presence of As antisite defects. The experimentally-determined hopping energy at the Curie temperature is roughly constant over a series of samples whose conductivities vary more than 10^4 and whose hole concentrations vary more than 10^2. Thus in this regime the hopping energy is an excellent predictor of the Curie temperature for a sample, in agreement with the theory.

5 pages, 4 figures

References in corpus (4)

• Atom-by-Atom Substitution of Mn in GaAs and Visualization of their Hole-Mediated Interactions
• Multiband tight-binding model of local magnetism in GaMnAs
• Antisite effect on ferromagnetism in (Ga,Mn)As
• Spin-orientation-dependent spatial structure of a magnetic acceptor state in a zincblende semiconductor

Cited by in corpus (13)

• Controlling Curie temperature in (Ga,Ms)As through location of the Fermi level within the impurity band
• Origin and control of ferromagnetism in dilute magnetic semiconductors and oxides
• Interplay between carrier localization and magnetism in diluted magnetic and ferromagnetic semiconductors
• Stoichiometric growth of high Curie temperature heavily-alloyed GaMnAs
• Electrical transport and ferromagnetism in Ga1-xMnxAs synthesized by ion implantation and pulsed-laser melting
• Interplay between localization and magnetism in (Ga,Mn)As and (In,Mn)As
• Hysteretic magnetoresistance and thermal bistability in a magnetic two-dimensional hole system
• Temperature dependence of the electronic structure and Fermi-surface reconstruction of Eu(1-x)Gd(x)O through the ferromagnetic metal-insulator transition
• Thermodynamic and thermoelectric properties of (Ga,Mn)As and related compounds
• Compensation-dependence of magnetic and electrical properties in Ga1-xMnxP
• Phase diagram of a ferromagnetic semiconductor. The origin of superparamagnetism
• Bismuth doping induced enhancement of the spin-orbit coupling strength in the prototype dilute ferromagnetic semiconductor (Ga,Mn)As: a review
• Small quantum dots of diluted magnetic III-V semiconductor compound