On the isotope effect in thermal conductivity of silicon

The thermal conductivity κ(T) of single crystals of silicon with two different isotopic compositions: natural and 99.983% enriched 28Si, was investigated in the temperature range from 0.5 K to 300 K. The enriched 28Si sample has very high thermal conductivity maximum of 290 W cm–1K–1 at Tmax = 26.5 K, about 7.5 times higher relative to the conductivity of natSi with natural isotope abundance. The isotope effect decreases with temperature increase, being 10 ± 2% at room temperature. The data are discussed briefly within the Ambegaocar's theory of isotope effect. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)