Surface structures of Sn on Mo(1 1 0) surface investigated by RHEED

Abstract

The surface structures of tin deposited on a Mo(1 1 0) surface have been investigated by reflection high-energy electron diffraction (RHEED), and a phase diagram of two-dimensional surface structures for variations of substrate temperature and coverage of several monolayers was obtained. Five kinds of surface structures were observed according to changes of coverage and annealing temperature. Less than 0.8 ML of Sn thickness, the α , β , γ and δ structures appeared in order with elevating temperature of the substrate, and above 0.8 ML, the α , γ , δ and ε structures similarly appeared. They are all commensurate structures. Dense direction of each structure is parallel to the [0 0 1]Mo in the α and ε structure, while those in the γ and δ structure is parallel to [1 1 0]Mo. The ε structure has the same atomic arrangement of bcc(1 1 0) plane rotated by 54 . 7 ∘ from Mo(1 1 0) plane with elongation by 6 / 3 times.