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Published on: December 3, 2013
Anomalous Hall effect in field-effect structures of (Ga,Mn)As.
D Chiba1, A Werpachowska, M Endo
1Semiconductor Spintronics Project, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Sanban-cho 5, Chiyoda-ku, Tokyo 102-0075, Japan.
Physical Review Letters
|April 7, 2010
Summary
The anomalous Hall effect in (Ga,Mn)As semiconductor structures shows unexpected temperature-dependent sign changes in conductance. This behavior is linked to Curie temperature and channel disorder, revealing new insights into magnetic semiconductor physics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Semiconductor Physics
Background:
- The anomalous Hall effect (AHE) is crucial for understanding charge transport in magnetic materials.
- Metal-insulator-semiconductor (MIS) structures offer tunable carrier densities, ideal for studying fundamental transport phenomena.
- (Ga,Mn)As is a key ferromagnetic semiconductor with potential spintronic applications.
Purpose of the Study:
- To investigate the anomalous Hall effect in thin (Ga,Mn)As layers within MIS structures.
- To explore the influence of varying Mn and hole densities on AHE properties.
- To analyze the temperature dependence and sign changes of the anomalous Hall conductance.
Main Methods:
- Fabrication of MIS structures with (Ga,Mn)As channels.
- Tuning Mn and hole densities using gate electric fields.
- Electrical transport measurements across a wide temperature range.
Main Results:
- Observed strong and unanticipated temperature dependence of anomalous Hall conductance (sigma(xy)).
- Demonstrated sign changes in sigma(xy) in samples with high Curie temperatures.
- Recovered the established scaling relation between sigma(xy) and longitudinal conductivity (sigma(xx)) for more disordered channels.
Conclusions:
- The study reveals complex AHE behavior in thin (Ga,Mn)As films, influenced by temperature and disorder.
- Sign changes in AHE provide critical insights into spin-dependent scattering mechanisms.
- Findings contribute to the understanding of charge and spin transport in magnetic semiconductors.
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