Heat capacity of isotopically enriched 28Si, 29Si and 30Si in the temperature range 4Â K<T<100Â K

The heat capacity of isotopically enriched 28Si, 29Si, 30Si samples has been measured in the temperature range between 4 and 100 K. The heat capacity of Si increases with isotopic mass. The values of the initial Debye temperature ΘD(0) for the three isotopic varieties of silicon have been determined. Good agreement with the theoretical dependence of the heat capacity on isotopic mass has been found.