Strong surface-termination effect on electroresistance in ferroelectric tunnel junctions

Hiroyuki Yamada, Atsushi Tsurumaki-Fukuchi, Masaki Kobayashi, Takuro Nagai, Yoshikiyo Toyosaki, Hiroshi Kumigashira, Akihito Sawa

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)

Abstract

Tunnel electroresistance in ferroelectric tunnel junctions (FTJs) has attracted considerable interest, because of a promising application to nonvolatile memories. Development of ferroelectric thin-film devices requires atomic-scale band-structure engineering based on depolarization-field effects at interfaces. By using FTJs consisting of ultrathin layers of the prototypical ferroelectric BaTiO3, it is demonstrated that the surface termination of the ferroelectric in contact with a simple-metal electrode critically affects properties of electroresistance. BaTiO3 barrier-layers with TiO2 or BaO terminations show opposing relationships between the polarization direction and the resistance state. The resistance-switching ratio in the junctions can be remarkably enhanced up to 105% at room temperature, by artificially controlling the fraction of BaO termination. These results are explained in terms of the termination dependence of the depolarization field that is generated by a dead layer and imperfect charge screening. The findings on the mechanism of tunnel electroresistance should lead to performance improvements in the devices based on nanoscale ferroelectrics.

Original languageEnglish
Pages (from-to)2708-2714
Number of pages7
JournalAdvanced Functional Materials
Volume25
Issue number18
DOIs
Publication statusPublished - 2015 May 13
Externally publishedYes

Keywords

  • electroresistance
  • ferroelectric tunnel junctions
  • metal-oxide interfaces
  • surface termination

ASJC Scopus subject areas

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

Fingerprint Dive into the research topics of 'Strong surface-termination effect on electroresistance in ferroelectric tunnel junctions'. Together they form a unique fingerprint.

Cite this