Using first-principles calculations,the contact between the scandium(Sc) and semiconducting carbon nanotube(CNT) is investigated.This is one of the best quality of n-type contacts.Two junction models with(8,0) CNT on low-index Sc surfaces are constructed to elucidate the structural and electronic properties of Sc/CNT junctions.Analyses based on density of states and charge difference reveal that strong chemical bonds are formed between Sc and C atoms due to hybrid states of Sc 3d state and C 2π state.With respect to Ti(0001)/CNT junction,we find the dipole layer formed at the interface of Sc(0001)/CNT is comparable with that of Ti(0001)/CNT but gives a negative barrier at the interface.This indicates that the excellent contact properties of Sc metal electrode are caused by its low work function and excellent binding with CNT.
