title: Metal-Insulator Transition Driven by Vacancy Ordering in GeSbTe Phase Change Materials.
abstract: Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows.
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Valeria
authors.initials: V
authors.lastname: Bragaglia
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.|Dipartimento di Fisica, Università di Roma "Tor Vergata", Via della Ricerca Scientifica 1, I-00133 Rome, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Arciprete
authors.affiliation: Institut für Theoretische Festkörperphysik and JARA, RWTH Aachen University, D-52056 Aachen, Germany.|Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Institute for Microelectronics and Microsystems (IMM), Consiglio Nazionale delle Ricerche (CNR), VIII Strada, 5-95121 Catania, Italy.
authors.forename: Antonio Massimiliano
authors.initials: AM
authors.lastname: Mio
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Zallo
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Karthick
authors.initials: K
authors.lastname: Perumal
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Giussani
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Stefano
authors.initials: S
authors.lastname: Cecchi
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Jos Emiel
authors.initials: JE
authors.lastname: Boschker
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Riechert
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Stefania
authors.initials: S
authors.lastname: Privitera
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Rimini
authors.affiliation: Institut für Theoretische Festkörperphysik and JARA, RWTH Aachen University, D-52056 Aachen, Germany.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Mazzarello
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Calarco