Optical properties of alkali metal binary and ternary graphite intercalation compounds

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6598938

Yang, M H

Optical reflectance of the stage 2-4 graphite potassium intercalation compounds in the range 0.2-6 eV has been measured and the experimental dielectric function epsilon(Omega) has been derived from a Kramers-Kronig analysis. The parameters of a stage-dependent two-dimensional tight binding model Hamiltonian are obtained by comparison of the calculated interband dielectric function with the experimental data. The narrow peaks associated with low energy interband transitions between graphitic ..pi..* conduction bands observed in the third and fourth stage K-GICs are found to occur at photon energies approximately equal to the difference of the electrostatic potential energy between bounding and interior graphite layers. The results of a comparative optical reflectance study at room temperature of the stage 1 and stage 2 CsBi/sub x/- and KHg-graphite intercalation compounds (GICs) in the energy range 0.2-10 eV are also presented. A Kramers-Kronig analysis is carried out to determine the dielectric function epsilon(Omega) = epsilon/sub 1/(Omega) + i epsilon/sub 2/(Omega) and the intra- and interband contributions to epsilon(Omega) are identified. The dielectric function for the respective compounds are analyzed in terms of a schematic density of states model involving contributions from two-dimensional graphite ..pi.. band(s) and intercalate bands. The analysis of the optical data indicates that for CsBi/sub x/- GICs the electrical transport properties should be dominated by the light carbon ..pi.. band electrons in contrast to the KHg-GICs, where the analysis indicate they should strongly depend on free carriers in both the ..pi..* and the intercalate band(s).

• Research Organization: Kentucky Univ., Lexington (USA)
• OSTI ID: 6598938
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
360603* -- Materials-- Properties
ALKALI METAL COMPOUNDS
BISMUTH COMPOUNDS
CARBON
CESIUM COMPOUNDS
CLATHRATES
DIELECTRIC PROPERTIES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTAL MINERALS
ELEMENTS
GRAPHITE
MERCURY COMPOUNDS
MINERALS
NONMETALS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
SUPERCONDUCTIVITY