Electrical, magneto-, and optical conductivity of quasicrystals in the Al-Re-Pd system
| Autor: | Andrea Bianchi, H. R. Ott, F. Bommeli, U. Gubler, M. A. Chernikov, Leonardo Degiorgi |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Physical Review B. 55:5730-5735 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.55.5730 |
| Popis: | Measurements of the electrical conductivity \ensuremath{\sigma}(T) and magnetoconductivity \ensuremath{\Delta}\ensuremath{\sigma}(H) of icosahedral ${\mathrm{Al}}_{70}$${\mathrm{Re}}_{10}$${\mathrm{Pd}}_{20}$ and ${\mathrm{Al}}_{70}$${\mathrm{Re}}_{8.6}$${\mathrm{Pd}}_{21.4}$ quasicrystals at low temperatures and in high magnetic fields H are reported. Below 0.2nK, \ensuremath{\sigma} of ${\mathrm{Al}}_{70}$${\mathrm{Re}}_{10}$${\mathrm{Pd}}_{20}$ varies as \ensuremath{\sigma}(T)=${\mathrm{\ensuremath{\sigma}}}_{0}$+${\mathrm{aT}}^{1\mathrm{/}2}$ with ${\mathrm{\ensuremath{\sigma}}}_{0}$=30 ${\mathrm{\ensuremath{\Omega}}}^{\mathrm{\ensuremath{-}}1}$${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ and a0. The conductivity decreases with increasing magnetic field. For ${\mathrm{Al}}_{70}$${\mathrm{Re}}_{8.6}$${\mathrm{Pd}}_{21.4}$ \ensuremath{\sigma}(T) decreases with decreasing T and saturates at the level ${\mathrm{\ensuremath{\sigma}}}_{0}$=1.7n${\mathrm{\ensuremath{\Omega}}}^{\mathrm{\ensuremath{-}}1}$${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ below 0.1nK. In magnetic fields up to 40 kOe, \ensuremath{\Delta}\ensuremath{\sigma}(H) is negative below 1 K and \ensuremath{\sigma}(T,H) remains temperature-independent at the lowest temperatures. The optical conductivity \ensuremath{\sigma}(\ensuremath{\omega}) is obtained from reflectivity data in the frequency range between 15 and ${10}^{5}$${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. The main contributions to \ensuremath{\sigma}(\ensuremath{\omega}) are a broad absorption signal centered at about 0.1neV and a sizable peak with its maximum at 2.6neV. |
| Databáze: | OpenAIRE |
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