Ultranarrow optical absorption and two-phonon excitation spectroscopy of Cu2O paraexcitons in a high magnetic field.

Physical review letters · 2007 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 3440

Study snapshot

PublicationPhysical review letters · 2007

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

We show that in a magnetic field B the otherwise forbidden lowest exciton in Cu2O (paraexciton of Gamma(2)(+) symmetry) gives rise to a narrow absorption line of 80 neV at a temperature of 1.2 K. The B2 dependence of the field-induced oscillator strength and the low energy shift DeltaE with increasing field strength are measured. From two-phonon excitation spectroscopy measurements we derive by a merely kinematical analysis a very reliable value for the paraexciton mass. A blueshift and a broadening of the absorption line are observed for increasing excitation intensity. These observations are discussed in connection with a Bose-Einstein condensation of paraexcitons in Cu2O.

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AI evidence extraction

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Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

In a magnetic field, the otherwise forbidden lowest exciton (paraexciton) in Cu2O produced a narrow absorption line (80 neV) at 1.2 K. The study measured a B^2 dependence of field-induced oscillator strength and an energy shift with increasing field strength, and derived a paraexciton mass from two-phonon excitation spectroscopy. Increasing excitation intensity caused a blueshift and broadening of the absorption line; these observations were discussed in connection with possible Bose-Einstein condensation of paraexcitons.

Outcomes measured

optical absorption line width
field-induced oscillator strength (B^2 dependence)
energy shift (DeltaE) with magnetic field
paraexciton mass (from two-phonon excitation spectroscopy)
blueshift and broadening with increasing excitation intensity

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "high magnetic field",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "optical absorption line width",
    "field-induced oscillator strength (B^2 dependence)",
    "energy shift (DeltaE) with magnetic field",
    "paraexciton mass (from two-phonon excitation spectroscopy)",
    "blueshift and broadening with increasing excitation intensity"
  ],
  "main_findings": "In a magnetic field, the otherwise forbidden lowest exciton (paraexciton) in Cu2O produced a narrow absorption line (80 neV) at 1.2 K. The study measured a B^2 dependence of field-induced oscillator strength and an energy shift with increasing field strength, and derived a paraexciton mass from two-phonon excitation spectroscopy. Increasing excitation intensity caused a blueshift and broadening of the absorption line; these observations were discussed in connection with possible Bose-Einstein condensation of paraexcitons.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "Cu2O",
    "paraexciton",
    "magnetic field",
    "optical absorption",
    "two-phonon excitation spectroscopy",
    "oscillator strength",
    "energy shift",
    "exciton mass",
    "blueshift",
    "line broadening",
    "Bose-Einstein condensation"
  ],
  "suggested_hubs": []
}

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Identifiers and source

DOI: 10.1103/physrevlett.99.217403
PubMed: 18233254

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