Roughening transition on the (110) face of argon: A molecular dynamics study

Abstract

Using molecular dynamics technique, we studied the temperature dependence of the structure of a solid argon (110) face. For temperatures T>0.7 T m ( T m = 81.5 K melting point temperature) the Arrhenius behaviour of the surface point defect concentration breaks down. Point defects production becomes nearly athermal in this temperature range and therefore the surface structure is interpreted as the result of a surface roughening process occuring at T= T c≅0.7 T m. A three level surface roughening model has been fitted on the evaluated concentration of surface point defects; the resulting atomic bond energy is in reasonable agreement with the corresponding value estimated from the experimental sublimation energy. Recent experimental results of helium scattering on (110) surfaces of copper are in qualitative agreement with our conclusions.