Giant multiferroic effects in topological GeTe-Sb2Te3 superlattices

Autor: Junji Tominaga, Alexander V Kolobov, Paul J Fons, Xiaomin Wang, Yuta Saito, Takashi Nakano, Muneaki Hase, Shuichi Murakami, Jens Herfort, Yukihiko Takagaki
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: Science and Technology of Advanced Materials, Vol 16, Iss 1 (2015)
Druh dokumentu: article
ISSN: 1468-6996
1878-5514
DOI: 10.1088/1468-6996/16/1/014402
Popis: 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 on d-electrons of transition metals. Here we report that in [(GeTe)2(Sb2Te3)l]m superlattice films (where l and m are 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. By ab initio computer simulations, it is revealed that the multiferroic properties are induced due to the breaking of spatial inversion symmetry when the p-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.
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