Temperature-dependent thermal conductivity of Ge₂Sb₂Te₅ polymorphs from 80 to 500 K

We report the thermal conductivity of amorphous, cubic, and hexagonal Ge 2 Sb Te 5 using time-domain thermoreflectance from 80 to 500 K. The measured conductivities are 0.20 W m −1 K for amorphous , 0.63 cubic phase, 1.45 phase at room temperature. For increases monotonically with temperature when T < 300 K, showing a typical glass-like dependence, dramatically after heating up 435 due partial crystallization phase. electronic contribution is significant. lattice shows relatively low value 0.47 has dependence > 100 suggesting that phonon–phonon scattering dominates its conductivity. Although similar grain size trend like indicating high concentration vacancies strongly scatter heat-carrying phonons. These transport mechanisms polymorphs help improve design change memory devices more energy-efficient non-volatile memory.