Investigation of the structure and properties of rhombohedral Cu–Ge–Te alloys by ab initio calculations

Crystallization property of amorphous GeTe can be significantly improved by doping Cu. However, the effect of Cu on the structure and electrical properties of crystalline GeTe is not clear, which is of great importance for phase-change memory. In this work, we have studied the effect of Cu on the structure and properties of crystalline GeTe by means of ab initio calculations. The results show that it is energetically favorable to obtain rhombohedral structured CunGe32–m–nTe32 films by co-sputtering defective Ge32–mTe32 and Cu as characterized by the negative formation energies. The doped Cu has slight effect on the structure property and chemical bonding of GeTe but has remarkable effect on the electrical properties. The results show that CunGe32–nTe32 alloys might be a good candidate material for phase-change memory.