Abstract
We report the results of optical reflectivity measurements on MBe13(M=U,Ce,Th) from 0.1 to 30 eV at T=300 K. The dielectric function ()=1+i2() is determined from a Kramers-Kronig analysis of the data. The intraband and interband contributions to () were separated via a low-energy Drude analysis. The following free-carrier plasma frequencies were obtained: p(UBe13)=5.9 eV, p(CeBe13)=5.3 eV, and p(ThBe13)=4.4 eV. Estimated values for the optical mass of the free carriers fall in the range 1<mopt<2 for the three beryllides, consistent with the presence of a wide band at EF. If a value of mopt=1 is chosen, the values of p are consistent with 3.4 (UBe13), 2.8 (CeBe13), and 2.0 (ThBe13) free carriers per MBe13 formula unit. Prominent structure in 2,bound is observed in all three compounds at 2 and 13 eV and are tentatively assigned to Be(2s2p) transitions. M-atom-dependent structure in the spectra is also observed and identified with the d and f states near EF. The results for UBe13 are discussed in terms of recent energy-band calculations, but a true quantitatitve comparison of the data and theory will have to await calculation of the dielectric functions from the band-structure results.
Original language | English |
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Pages (from-to) | 4250-4257 |
Number of pages | 8 |
Journal | Physical Review B |
Volume | 35 |
Issue number | 9 |
DOIs | |
State | Published - 1987 |
ASJC Scopus subject areas
- Condensed Matter Physics