Abstract:
The anharmonic, multi-phonon (MP), and Oebye-Waller factor (OW)
contributions to the phonon limited resistivity (;0) of metals derived by
Shukla and Muller (1979) by the doubletime temperature dependent Green
function method have been numerically evaluated for Na and K in the high
temperature limit. The anharmonic contributions arise from the cubic and
quartic shift of phonons (CS, QS), and phonon width (W) and the interference
term (1). The QS, MP and OW contributions to I' are also derived
by the matrix element method and the results are in agreement with those
of Shukla and Muller (1979). In the high temperature limit, the contributions
to;O from each of the above mentioned terms are of the type BT2
For numerical calculations suitable expressions are derived for the
anharmonic contributions to ~ in terms of the third and fourth rank
tensors obtained by the Ewald procedure. The numerical calculation of
the contributions to;O from the OW, MP term and the QS have been done
exactly and from the CS, Wand I terms only approximately in the partial
and total Einstein approximations (PEA, TEA), using a first principle
approach (Shukla and Taylor (1976)). The results obtained indicate that
there is a strong pairwise cancellation between the: OW and MP terms,
the QS and CS and the Wand I terms.
The sum total of these contributions to;O for Na and K amounts to
4 to 11% and 2 to 7%, respectively, in the PEA while in the TEA they
amount to 3 to 7% and 1 to 4%, respectively, in the temperature range.
