Impurity band conduction in a high temperature ferromagnetic semiconductor

K. S. Burch, D. B. Shrekenhamer, E. J. Singley, J. Stephens, B. L. Sheu, R. K. Kawakami, P. Schiffer, N. Samarth, D. D. Awschalom, D. N. Basov

Research output: Contribution to journalArticlepeer-review

169 Scopus citations


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 [σ1(ω)] 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 σ1(ω) 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.

Original languageEnglish (US)
Article number087208
JournalPhysical review letters
Issue number8
StatePublished - 2006

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


Dive into the research topics of 'Impurity band conduction in a high temperature ferromagnetic semiconductor'. Together they form a unique fingerprint.

Cite this