title: Giant multiferroic effects in topological GeTe-Sb2Te3superlattices.
abstract: Multiferroics, materials in which both magnetic and electric fields can induce each other, resulting in a magnetoelectric response, have been attracting increasing attention, although the induced magnetic susceptibility and dielectric constant are usually small and have typically been reported for low temperatures. The magnetoelectric response usually depends ond-electrons of transition metals. Here we report that in [(GeTe)2(Sb2Te3)l]msuperlattice films (wherelandmare integers) with topological phase transition, strong magnetoelectric response may be induced at temperatures above room temperature when the external fields are applied normal to the film surface. Byab initiocomputer simulations, it is revealed that the multiferroic properties are induced due to the breaking of spatial inversion symmetry when thep-electrons of Ge atoms change their bonding geometry from octahedral to tetrahedral. Finally, we demonstrate the existence in such structures of spin memory, which paves the way for a future hybrid device combining nonvolatile phase-change memory and magnetic spin memory.
authors.affiliation: Nanoelectronics Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba 305-8562, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Tominaga
authors.affiliation: Nanoelectronics Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba 305-8562, Japan.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kolobov
authors.affiliation: Nanoelectronics Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba 305-8562, Japan.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Fons
authors.affiliation: Nanoelectronics Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba 305-8562, Japan.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Nanoelectronics Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba 305-8562, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Nanoelectronics Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba 305-8562, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.affiliation: Faculty of Pure and Applied Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8573, Japan.
authors.forename: Muneaki
authors.initials: M
authors.lastname: Hase
authors.affiliation: Department of Physics & TIES, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Murakami
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Herfort
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Takagaki
keywords: GeTe-Sb2Te3; chalcogenide superlattice; computer simulation; magnetoresistance; multiferroics; phase change memory; spintronics; topological insulator