Lateral thermal expansion of Cu(110) surface studied with helium atom scattering

Abstract Lateral thermal expansion of the Cu(110) surface is investigated by helium atom scattering. The expansion coefficients in the [001] direction are evaluated from high-resolution helium diffraction measurements to be 2.02×10 −5 and 2.35×10 −5  K −1 under vacuum and under atomic hydrogen irradiation, respectively. In the presence of the atomic hydrogen the thermal expansion is enhanced by 1.4, consistent with previous observations of softening of CuCu bonding.