XAFS Analysis of Crystal GeCu2Te3 Phase Change Material

Abstract

The structure of crystal GeCu2Te3 was investigated by X-ray absorption fine structure (XAFS) measurement. We found that the Ge-Te interatomic distances obtained from XAFS are larger than those obtained from X-ray diffraction, and the Cu-Te distances are smaller. The averaged Ge-Te and Cu-Te distances obtained from XAFS are almost equal to the corresponding interatomic distances in amorphous GeCu2Te3. Therefore both crystal and amorphous GeCu2Te3 seem to be built up of the same local configurations of GeTe4 and CuTe4 tetrahedrons. This would be the reason why the phase change in GeCu2Te3 occurs very fast.