Phase stability and temperature effect in ScX (X=S, Se and Te) compounds

•The structural stability and temperature effect in allotropes of scandium chalcogenides ScX (X=S, Se and Te) are studied.•The phase transition from hcp structure to β-hcp structure in ScTe is found at finite temperature.•The energy barrier between hcp and β-hcp structure of ScTe suggests that the phase transformation can occur easily.