Phonon dispersion relationship and oxygen isotope effect in superconductor LaFeAsO

In this paper we have calculated ab initially the phonon dispersion relationship of superconductor LaFeAsO and investigated a main property in the superconductor, oxygen isotope effect. On the basis of this phonon dispersion relationship we have found the fact that an important reason of the oxygen isotope effect is connected with the phonon. Also, this result agrees well with the experimental data where the power index of oxygen isotope effect in superconductor LaFeAsO is small.