Thermoelectric Power of Lattice Vacancies in Gold

The change ΔS of the thermoelectric power of high-purity gold wires due to quenched-in lattice vacancies was measured between 4.2 and 220^∘{}K. The vacancy concentration was determined from the quenched-in electrical resistance at 4.2^∘{}K. From the value of ΔS at 200^∘{}K, where phonon-drag effects are negligible, the electronic part ΔSₑ of ΔS was calculated as a function of the temperature, using the Friedel theory. The phonon-drag part ΔSg was obtained from the equation ΔSg=ΔS-ΔSₑ. Vacancies were found to cause a reduction of the electronic part and of the phonon-drag part of the thermoelectric power. |ΔSₑ| and |ΔSg| reach a maximum at low temperatures. The phonon-scattering cross section of vacancies, as estimated from ΔSg assuming a pure Rayleigh-type scattering mechanism, indicates that phonons are scattered by vacancies predominantly through the strain field associated with the vacant lattice site.