Double exchange mechanisms for Mn doped III-V ferromagnetic semiconductors

Abstract

A microscopic model of indirect exchange interaction between transition metal impurities in dilute magnetic semiconductors (DMS) is proposed. The hybridization of the impurity d-electrons with the heavy hole band states is largely responsible for the transfer of electrons between the impurities, whereas Hund rule for the electron occupation of the impurity d-shells makes the transfer spin selective. The model is applied to such systems as $n-$type GaN:Mn and $p-$type (Ga,Mn)As, $p-$type (Ga,Mn)P. In $n-$type DMS with Mn${}^{2+/3+}$ impurities the exchange mechanisms is rather close to the kinematic exchange proposed by Zener for mixed-valence Mn ions. In $p-$type DMS ferromagnetism is governed by the kinematic mechanism involving the kinetic energy gain of heavy hole carriers caused by their hybridization with 3d electrons of Mn${}^{2+}$ impurities. Using the molecular field approximation the Curie temperatures $T_C$ are calculated for several systems as functions of the impurity and hole concentrations. Comparison with the available experimental data shows a good agreement.

Submitted to PRB

References in corpus (14)

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Cited by in corpus (15)

• Theory of ferromagnetic (III,Mn)V semiconductors
• On the character of states near the Fermi level in (Ga,Mn)As: impurity to valence band crossover
• Why RKKY exchange integrals are inappropriate to describe ferromagnetism in diluted magnetic semiconductors
• Superexchange in Dilute Magnetic Dielectrics: Application to (Ti,Co)O_2
• Ultrafast Magnetization Dynamics in Diluted Magnetic Semiconductors
• Three--body Correlation Effects on the Spin Dynamics of Double--Exchange Ferromagnets
• Improved-Sensitivity Integral SQUID Magnetometry of (Ga,Mn)N Thin Films in Proximity to Mg-doped GaN
• Magnetic properties of wurtzite (Ga,Mn)As
• Electronic structure of noble metal impurities in semiconductors: Cu in GaP
• Unconventional ferromagnetism and transport properties of (In,Mn)Sb dilute magnetic semiconductor
• Non-volatile bistability effect based on electrically controlled phase transition in scaled magnetic semiconductor nanostructures
• Bistability in a magnetic and nonmagnetic double-quantum-well structure mediated by the magnetic phase transition
• Electronic States and Magnetism of Mn Impurities and Dimers in Narrow-Gap and Wide-Gap III-V Semiconductors
• Collective excitations in a magnetically doped quantized Hall ferromagnet
• Orbital polaron in double exchange ferromagnets