Effect of Anisotropy of Elastic Energy on the Electron–Phonon Drag and Temperature Dependences of Thermal EMF in Potassium Crystals at Low Temperatures

Abstract

The effect of anisotropy of elastic energy on electron–phonon drag and thermoelectric phenomena in potassium crystals is studied. The temperature dependences of the thermal conductivity, thermal emf, and contributions to them from phonons of different polarizations are calculated. The calculation results are matched to the experimental data by varying the electron–phonon interaction constant for quasi-transverse phonons. It is established that the contribution of slow quasi-transverse phonons to the drag thermal emf of bulk potassium crystals is by an order of magnitude greater than the contribution of quasi-longitudinal phonons. The maximum values of the drag thermal emf in perfect potassium crystals are determined. It is shown that they do not depend on the electron–phonon interaction constants, but are determined by the second-order elastic moduli and the electron density.