Skip to main content
Open Access Publications from the University of California

UC Irvine

UC Irvine Previously Published Works bannerUC Irvine

Far-infrared absorptivity of UPt3.


The absorptivity of the heavy-fermion compound UPt3 is measured from 2 to 1000 cm-1 (0.25"124 meV) at temperatures between 1.2 K and room temperature. Above 50 cm-1 (6.2 meV) the absorptivity is relatively temperature independent, while below that frequency the absorptivity is very temperature dependent, in accord with the dc resistivity. By performing a Kramers-Kronig transformation of the data, augmented with recently published results at higher frequencies, the complex conductivity is obtained. The low-temperature conductivity may be characterized by free carriers which undergo frequency-dependent scattering and have a concomitant frequency-dependent mass enhancement, ≫(), with ≫(0)=65. The data indicate a bare free-carrier plasma frequency of 2.1×104 cm-1 (2.6 eV). Combining these results with the measured specific heat for UPt3 gives for the low-frequency effective mass m*=240m, and for the optical band mass mb=3.7m. The carrier density is close to one electron per formula unit. The far-infrared absorptivity measurement indicates that the scattering rate begins to rise with an 2 dependence, while the measured dc resistivity has a T2 dependence at temperatures below 2 K. To account for the far-infrared data, the carrier scattering rate "(,T) can be written as "(,T)1/42+(pT)2, with an experimental upper limit of p=1. This is not consistent with electron-electron scattering, for which p=2. © 1988 The American Physical Society.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View