0000000000223624

AUTHOR

James Hamlin

showing 3 related works from this author

Tuning the band gap of PbCrO4 through high-pressure: Evidence of wide-to-narrow semiconductor transitions

2014

The electronic transport properties and optical properties of lead(II) chromate (PbCrO4) have been studied at high pressure by means of resistivity, Hall-effect, and optical-absorption measurements. Band-structure first-principle calculations have been also performed. We found that the low-pressure phase is a direct band-gap semiconductor (Eg = 2.3 eV) that shows a high resistivity. At 3.5 GPa, associated to a structural phase transition, a band-gap collapse takes place, becoming Eg = 1.8 eV. At the same pressure the resistivity suddenly decreases due to an increase of the carrier concentration. In the HP phase, PbCrO4 behaves as an n-type semiconductor, with a donor level probably associat…

Phase transitionCondensed Matter - Materials ScienceCondensed matter physicsChemistrybusiness.industryBand gapMechanical EngineeringMetals and AlloysMaterials Science (cond-mat.mtrl-sci)FOS: Physical sciencesSemiconductorMechanics of MaterialsImpurityElectrical resistivity and conductivityHall effectPhase (matter)Materials ChemistryElectronic band structurebusiness
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High Pressure Raman, Optical Absorption, and Resistivity Study of SrCrO4

2018

We studied the electronic and vibrational properties of monazite-type SrCrO4 under compression. The study extended the pressure range of previous studies from 26 to 58 GPa. The existence of two previously reported phase transitions was confirmed at 9 and 14 GPa, and two new phase transitions were found at 35 and 48 GPa. These transitions involve several changes in the vibrational and transport properties with the new high-pressure phases having a conductivity lower than that of the previously known phases. No evidence of chemical decomposition or metallization of SrCrO4 was detected. A tentative explanation for the reported observations is discussed.

Phase transitionPHASE-TRANSITION MCRO4 M PHOTOCATALYTIC PROPERTIESCondensed matter physicsChemistry02 engineering and technologyMCRO4 MConductivity021001 nanoscience & nanotechnology01 natural sciencesInorganic ChemistryPressure rangesymbols.namesakeElectrical resistivity and conductivityHigh pressurePHOTOCATALYTIC PROPERTIES0103 physical sciencesPHASE-TRANSITIONsymbolsPhysical and Theoretical ChemistryAbsorption (chemistry)010306 general physics0210 nano-technologyRaman spectroscopyChemical decompositionInorganic Chemistry
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ChemInform Abstract: Tuning the Band Gap of PbCrO4Through High-Pressure: Evidence of Wide-to-Narrow Semiconductor Transitions.

2014

Commercial polycrystalline and cleaved platelets from natural PbCrO4 are studied in a diamond anvil cell at ≤ 21 GPa.

congenital hereditary and neonatal diseases and abnormalitiesbusiness.industryBand gapChemistryA diamondmacromolecular substancesGeneral MedicineSemiconductorstomatognathic systemhemic and lymphatic diseasesHigh pressureparasitic diseasesOptoelectronicsCrystallitebusinessChemInform
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