title: Atomic Layering, Intermixing and Switching Mechanism in Ge-Sb-Te based Chalcogenide Superlattices.
abstract: GeSbTe-based chalcogenide superlattice (CSLs) phase-change memories consist of GeSbTe layer blocks separated by van der Waals bonding gaps. Recent high resolution electron microscopy found two types of disorder in CSLs, a chemical disorder within individual layers, and SbTe bilayer stacking faults connecting one block to an adjacent block which allows individual block heights to vary. The disorder requires a generalization of the previous switching models developed for CSL systems. Density functional calculations are used to describe the stability of various types of intra-layer disorder, how the block heights can vary by means of SbTe-based stacking faults and using a vacancy-mediated kink motion, and also to understand the nature of the switching process in more chemically disordered CSLs.
authors.affiliation: Engineering Dept, University of Cambridge, Cambridge CB2 1PZ, UK.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yu
authors.affiliation: Engineering Dept, University of Cambridge, Cambridge CB2 1PZ, UK.
authors.forename: John
authors.initials: J
authors.lastname: Robertson