ON THE CARRIER CONTRIBUTION TO THE ELASTIC-CONSTANTS IN ULTRATHIN FILMS OF IV-VI COMPOUNDS IN THE PRESENCE OF A PARALLEL MAGNETIC-FIELD

We study the carrier contribution to the elastic constants in ultrathi n films of IV-VI compounds in the presence of a parallel magnetic held on the basis of a new 2D carrier dispersion law. It is found, taking ultrathin films of PbS, PbSe and PbTe as examples, that the carrier co ntribution to the second and third order elastic constants increases w ith decreasing film thickness in various oscillatory manners. The magn etic field and the ultrathin structure enhance the numerical values of the same contribution. We have suggested an experimental method of de termining the said contribution in ultrathin materials having arbitrar y dispersion laws.