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RESEARCH PRODUCT
Possible superlattice formation in high-temperature treated carbonaceous MgB2 at elevated pressure
George SerghiouO. TschaunerDaniel ErrandoneaDaniel Errandoneasubject
SuperconductivityCondensed Matter - Materials SciencePhase transitionMaterials scienceCondensed matter physicsCondensed Matter - SuperconductivitySuperlatticeMaterials Science (cond-mat.mtrl-sci)FOS: Physical scienceschemistry.chemical_elementCondensed Matter PhysicsCrystallographic defectElectronic Optical and Magnetic MaterialsSuperconductivity (cond-mat.supr-con)Stress (mechanics)symbols.namesakechemistryCondensed Matter::SuperconductivityStress relaxationsymbolsElectrical and Electronic EngineeringBoronRaman spectroscopydescription
We report indications of a phase transition in carbonaceous MgB2 above 9 GPa at 300 K after stress relaxation by laser heating. The transition was detected using Raman spectroscopy and X-ray diffraction. The observed changes are consistent with a second-order structural transition involving a doubling of the unit cell along c and a reduction of the boron site symmetry. Moreover, the Raman spectra suggest a reduction in electron-phonon coupling in the slightly modified MgB2 structure consistent with the previously proposed topological transition in MgB2. However, further attributes including deviatoric stress, lattice defects, and compositional variation may play an important role in the observed phenomena.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-10-14 | Physica B: Condensed Matter |