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Slow relaxation of magnetoresistance in AlGaAs-GaAs quantum well structures quenched in a magnetic field.

Journal of physics. Condensed matter : an Institute of Physics journal · 2010 · Unclear · Insufficient evidence

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In selectively doped p-GaAs/AlGaAs structures, magnetoresistance showed slow relaxation after application/variation of an external magnetic field. The authors report that this slow relaxation persisted after efforts to exclude temperature fluctuation effects,…

Study snapshot

PublicationJournal of physics. Condensed matter : an Institute of Physics journal · 2010
Study typeother
Reported directionUnclear
Evidence ratingInsufficient

Abstract

We observed a slow relaxation of the magnetoresistance in response to an applied magnetic field in selectively doped p-GaAs-AlGaAs structures with a partially filled upper Hubbard band. We have paid special attention to excluding the effects related to temperature fluctuations. Although these effects are important, we have found that the general features of slow relaxation persist. This behavior is interpreted as related to the properties of the Coulomb glass formed by charged centers with account taken of spin correlations, which are sensitive to an external magnetic field. Variation of the magnetic field changes the numbers of the impurity complexes of different types. As a result, it affects the shape and depth of the polaron gap formed at the states belonging to the percolation cluster responsible for the conductance. The suggested model explains both the qualitative behavior and the order of magnitude of the slowly relaxing magnetoresistance.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother
Effect directionunclear
PopulationNot supplied
Sample sizeNot supplied
ExposureNot supplied
Evidence strengthInsufficientConfidence: 66% · Peer reviewed: yes

Main findings

In selectively doped p-GaAs/AlGaAs structures, magnetoresistance showed slow relaxation after application/variation of an external magnetic field. The authors report that this slow relaxation persisted after efforts to exclude temperature fluctuation effects, and interpret the behavior using a Coulomb-glass model with spin correlations affecting impurity complexes and the polaron gap relevant to conductance.

Outcomes measured

  • magnetoresistance relaxation
  • conductance changes
  • polaron gap shape/depth (model interpretation)

Limitations

  • No quantitative exposure parameters for the magnetic field are provided in the abstract (e.g., field strength, timing).
  • Temperature fluctuation effects are noted as important, though the authors attempted to exclude them; residual confounding cannot be assessed from the abstract.
  • No sample size or experimental replication details are provided in the abstract.
View raw extracted JSON
{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "applied magnetic field",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "magnetoresistance relaxation",
    "conductance changes",
    "polaron gap shape/depth (model interpretation)"
  ],
  "main_findings": "In selectively doped p-GaAs/AlGaAs structures, magnetoresistance showed slow relaxation after application/variation of an external magnetic field. The authors report that this slow relaxation persisted after efforts to exclude temperature fluctuation effects, and interpret the behavior using a Coulomb-glass model with spin correlations affecting impurity complexes and the polaron gap relevant to conductance.",
  "effect_direction": "unclear",
  "limitations": [
    "No quantitative exposure parameters for the magnetic field are provided in the abstract (e.g., field strength, timing).",
    "Temperature fluctuation effects are noted as important, though the authors attempted to exclude them; residual confounding cannot be assessed from the abstract.",
    "No sample size or experimental replication details are provided in the abstract."
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.66,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "magnetoresistance",
    "magnetic field",
    "GaAs",
    "AlGaAs",
    "quantum well",
    "Coulomb glass",
    "spin correlations",
    "Hubbard band",
    "polaron gap",
    "percolation cluster"
  ],
  "suggested_hubs": []
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1088/0953-8984/22/40/405301
PubMed: 21386578

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