The chalcogenide material GeSbTe is the prototype phase-change material, with widespread applications for optical media and random access memory. However, the full set of its independent elastic properties has not yet been published. In this study, we determine the elastic constants of the rocksalt GeSbTe, experimentally by X-ray diffraction (XRD) and residual stress and computationally by density functional theory (DFT). The stiffnesses (XRD-stress/DFT) in GPa are C = 41/58, C = 7/8, and C = 8/12, and the Zener ratio is 0.46/0.48. These values are important to understand the effect of elastic distortions and nonmelting processes on the performances of increasingly small phase change data bits.

We gratefully acknowledge funding from European FP6 framework program-EXCELL Project NoE 5157032, CSIC (NANO-CONTROL 201060E102), Spanish Ministry MICINN (Consolider FUNCOAT CSD2008-00023), and Junta de Andalucia (TEP217).