Related Experiment Video
Updated: Jul 19, 2026

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
Impurity band conduction in a high temperature ferromagnetic semiconductor
K S Burch1, D B Shrekenhamer, E J Singley
1Department of Physics, University of California, San Diego, California 92093-0319, USA. kburch@lanl.gov
Abstract:
The band structure of a prototypical dilute magnetic semiconductor (DMS), Ga1-xMnxAs, is studied across the phase diagram via infrared and optical spectroscopy. We prove that the Fermi energy (EF) resides in a Mn-induced impurity band (IB). Specifically the changes in the frequency dependent optical conductivity [sigma1(omega)] with carrier density are only consistent with EF lying in an IB. Furthermore, the large effective mass (m*) of the carriers inferred from our analysis of sigma1(omega) supports this conclusion. Our findings demonstrate that the metal to insulator transition in this DMS is qualitatively different from other III-V semiconductors doped with nonmagnetic impurities. We also provide insights into the anomalous transport properties of Ga1-xMnxAs.
More Related Videos
Related Concept Videos
Types of Semiconductors
Fermi Level
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
Semiconductors
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
Band Theory
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
Fermi Level Dynamics
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Ferromagnetism

