A Magnetoresistance Induced by a Nonzero Berry Phase in GeTe/Sb2Te3 Chalcogenide Superlattices

Junji Tominaga, Yuta Saito, Kirill Mitrofanov, Nobuki Inoue, Paul Fons, Alexander V. Kolobov, Hisao Nakamura, Noriyuki Miyata

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The chalcogenide alloy Ge–Sb–Te (GST) has not only been used in rewritable digital versatile discs, but also in nonvolatile electrical phase change memory as a key recording material. Although GST has been believed for a long time not to show magnetic properties unless doped with magnetic impurities, it has recently been reported that superlattices (SLs) with the structure [(GeTe)L(Sb2Te3)M]N (where L, M, and N are usually integers) have a large magnetoresistance at room temperature for particular combinations of L and M. Here it is reported that when [(GeTe)L(Sb2Te3)M]N chalcogenide SL films are thermally annealed at 470 K and cooled down to room temperature under an external magnetic field accompanied by current pulse injections, a large magnetoresistance change (>2500 Ω) is induced. This study shows that the phenomenon has a strong correlation with the GeTe thickness and the periodic structure of the SL films, and that it is induced by the structural phase transition between electrically nonpolar and polar phases in the GeTe layers in the SLs. This study proposes that the relationship between the polar (ferroelectric) phase and the Berry curvature in the SLs is responsible for the magnetoresistance change.

Original languageEnglish
Article number1702243
JournalAdvanced Functional Materials
Volume27
Issue number40
DOIs
Publication statusPublished - 2017 Oct 26
Externally publishedYes

Keywords

  • anomalous Hall effect
  • Berry phase
  • chalcogenide superlattice
  • magnetoresistance
  • phase change memory

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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    Tominaga, J., Saito, Y., Mitrofanov, K., Inoue, N., Fons, P., Kolobov, A. V., Nakamura, H., & Miyata, N. (2017). A Magnetoresistance Induced by a Nonzero Berry Phase in GeTe/Sb2Te3 Chalcogenide Superlattices. Advanced Functional Materials, 27(40), [1702243]. https://doi.org/10.1002/adfm.201702243