Thermoelectric and Thermal Properties of a (GeTe)₂/Sb₂Te₃ Interfacial Phase‐Change Memory Device

Abstract

The thermoelectric and thermal properties of an interfacial phase‐change memory (iPCM) device, in which the resistive switching layer (RSL) is the (GeTe)2/Sb2Te3 superlattice, are investigated. To clarify the effects of intralayer exchange of the GeTe layer and the van der Waals (vdW) gap in the superlattice, a device model consisting of a 10 nm‐scale RSL connected to W(111) electrodes is focused. The two (GeTe)2/Sb2Te3 superlattice structures and one intercalation structure of GeTe in Sb2Te3, which are called inverted Petrov (IP), Ferro (FR), and Kooi–De Hosson (KH) structures, are examined. The calculated thermoelectric properties suggest that doping or charge trapping can enhance the difference in the thermoelectric properties and electric resistance contrast due to a phase change. Phonon thermal transport is almost ballistic for all three structural phases, whereas the KH structure shows the lowest thermal conductance and a large effect of phonon–phonon scattering. The theoretical calculations show that thermal and thermoelectric properties could be useful for identifying local structural change and atomic rearrangement.