Righi-Leduc- and Hall-Coefficient Measurements on Na and K

Abstract

Experimental results on the Righi-Leduc and Hall coefficients of K and Na over the range 2-100 K are reported. The Righi-Leduc coefficient does not behave as expected but shows a large peak at low temperatures; the origin of this peak is not clear but it may be due to phonon drag. The measurements have been made over a wide field range (0.05-0.95 T) and it is found that the limiting low-temperature behavior is sensitive to field. At low temperatures and high fields, the Wiedemann-Franz law is found to hold to within 1%, which suggests that the thermal conductivity of the lattice must be small in comparison with that of the electrons; in addition, the Righi-Leduc and Hall coefficients exhibit the expected magnitude appropriate to a closed electronlike Fermi surface.