VACANCIES AND THE ELECTRICAL-RESISTIVITY OF POTASSIUM

The authors have measured the electrical resistivity rho (T) of potassium to a relative accuracy of 0.2% in the temperature range 200K<T<330K. Comparison with the theoretical results of Shukla and Taylor (1976) (corrected for the effect of the Debye-Waller factor, multiphonon processes and non-local screening in the form factor) reveals an exponential increase in the measured rho (T) as T approaches the melting temperature. Assuming that this phenomenon is due to vacancy formation the authors are able to deduce a value of the formation enthalpy Hv which is in good accord with the theoretical prediction of Jacucci and Taylor (1979). However a careful error analysis shows that the combined effects of theoretical and experimental uncertainties are sufficiently large to place Hv at any point in the range from 0.2 eV to 0.6 eV. They therefore conclude that measurement of the high-temperature electrical resistivity of a metal is not a useful tool for investigating vacancy formation.