Impurity Band Conduction in a High Temperature Ferromagnetic Semiconductor

Abstract

The band structure of a prototypical dilute ferromagnetic semiconductor, Ga${}_{1-x}$Mn${}_x$As, is studied across the phase diagram via optical spectroscopy. We prove that the Fermi energy ($E_F$) resides in a Mn induced impurity band (IB). This conclusion is based upon careful analysis of the frequency and temperature dependence of the optical conductivity (${\sigma }_1(\omega ,T)$). From our analysis of ${\sigma }_1(\omega ,T)$ we infer a large effective mass ($m^{\ast }$) of the carriers, supporting the view that conduction occurs in an IB. Our results also provide useful insights into the transport properties of Mn-doped GaAs.

4 pages, 4 figures

References in corpus (3)

• Multiband tight-binding model of local magnetism in GaMnAs
• Ellipsometric study of the Electronic Structure of GaMnAs and LT-GaAs
• Influence of annealing parameters on the ferromagnetic properties of optimally passivated (Ga,Mn)As epilayers

Cited by in corpus (16)

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• Optical Properties of III-Mn-V Ferromagnetic Semiconductors
• Ultrafast demagnetization in the sp-d model: a theoretical study
• Weak localization in GaMnAs: evidence of impurity band transport
• Metal-insulator transition by isovalent anion substitution in Ga1-xMnxAs: Implications to ferromagnetism
• Determination of the infrared complex magneto-conductivity tensor in itinerant ferromagnets from Faraday and Kerr measurements
• Spin dynamics in (III,Mn)V ferromagnetic semiconductors: the role of correlations
• Long-range ferromagnetic correlations between Anderson impurities in a semiconductor host
• Magnetic circular dichroism from the impurity band in III-V diluted magnetic semiconductors
• The Crossover from Impurity to Valence Band in Diluted Magnetic Semiconductors: The Role of the Coulomb Attraction by Acceptor
• Large-Scale Monte Carlo Study of a Realistic Lattice Model for Ga_(1-x)Mn_xAs
• Inter-impurity and impurity-host magnetic correlations in semiconductors with low-density transition-metal impurities
• Disorder Enhanced Spin Polarization in Diluted Magnetic Semiconductors
• Perspectives in spintronics: magnetic resonant tunneling, spin-orbit coupling, and GaMnAs