Infrared conductivity of hole accumulation and depletion layers in (Ga,Mn)As- and (Ga,Be)As-based electric field-effect devices

Chapler, B. C., Mack, S., Ju, L., Elson, T. W., Boudouris, B. W., Namdas, E., Yuen, J. D., Heeger, A. J., Samarth, N., Di Ventra, M., Segalman, R. A., Awschalom, D. D., Wang, F. and Basov, D. N. (2012) Infrared conductivity of hole accumulation and depletion layers in (Ga,Mn)As- and (Ga,Be)As-based electric field-effect devices. Physical Review B, 86 16: . doi:10.1103/PhysRevB.86.165302

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Author Chapler, B. C.
Mack, S.
Ju, L.
Elson, T. W.
Boudouris, B. W.
Namdas, E.
Yuen, J. D.
Heeger, A. J.
Samarth, N.
Di Ventra, M.
Segalman, R. A.
Awschalom, D. D.
Wang, F.
Basov, D. N.
Title Infrared conductivity of hole accumulation and depletion layers in (Ga,Mn)As- and (Ga,Be)As-based electric field-effect devices
Journal name Physical Review B   Check publisher's open access policy
ISSN 1098-0121
Publication date 2012-10-01
Year available 2012
Sub-type Article (original research)
DOI 10.1103/PhysRevB.86.165302
Open Access Status File (Publisher version)
Volume 86
Issue 16
Total pages 8
Place of publication College Park, MD, United States
Publisher American Physical Society
Collection year 2013
Language eng
Formatted abstract
We have fabricated electric double-layer field-effect devices to electrostatically dope our active materials, either x = 0.015 Ga1−xMnxAs or x = 3.2 × 10−4 Ga1−xBexAs. The devices are tailored for interrogation of electric field-induced changes to the frequency-dependent conductivity in the accumulation or depletion layers of the active material via infrared (IR) spectroscopy at room temperature. The spectra of the (Ga,Be)As-based device reveal electric field-induced changes to the IR conductivity consistent with an enhancement or reduction of the Drude response in the accumulation and depletion polarities, respectively. The spectroscopic features of this
device are all indicative of metallic conduction within the GaAs host valence band (VB). For the (Ga,Mn)As-based device, the spectra show enhancement of the far-IR itinerant carrier response and broad mid-IR resonance upon hole accumulation, with a suppression of these features in the depletion polarity. These latter spectral features
demonstrate that conduction in ferromagnetic (FM) Ga1−xMnxAs is distinct from genuine metallic behavior due to extended states in the host VB. Furthermore, these data support the notion that a Mn-induced impurity band plays a vital role in the electrodynamics of FM Ga1−xMnxAs. We add that a sum-rule analysis of the spectra of our devices suggests that the Mn or Be doping does not lead to a substantial renormalization of the GaAs host VB.
Keyword Diluted magnetic semiconductors
Ferromagnetic semiconductors
Valence band
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
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Citation counts: TR Web of Science Citation Count  Cited 8 times in Thomson Reuters Web of Science Article | Citations
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