Tunable tunneling electroresistance in ferroelectric tunnel junctions by mechanical loads

Xin Luo, Biao Wang, Yue Zheng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

42 Citations (Scopus)

Abstract

Combining nonequilibrium Green functions approach with density functional theory, effects of the applied mechanical loads on polarization, electrostatic potential, and tunneling conductance of a ferroelectric tunneling junction (FTJ) have been investigated. Using the first principle calculations, we show that compressive strains can induce and enhance the polarization in ferroelectric tunnel barriers, and practically achieve ferroelectricity in two unit cell thickness under a -2.2% compressive strain. More importantly, mechanical strains can significantly change the effective electrostatic potential in FTJ and thus control its tunneling conductance, which is defined as giant piezoelectric resistance (GPR) effect. Our calculations indicate that GPR effect is particularly significant near the paraelectric/ferroelectric phase transition, and increases exponentially with the barrier thickness. Furthermore, it is also found that defects of oxygen vacancies and nitrogen doping have little impact on GPR ratio of strained FTJ. Because of its high-sensitivity to external mechanical loads, FTJ with GPR effect should be adequate for applications in agile mechanical sensors, transducers, and other multifunctional devices.
Original languageEnglish
Pages (from-to)1649-1656
Number of pages8
JournalACS Nano
Volume5
Issue number3
DOIs
Publication statusPublished - 22 Mar 2011
Externally publishedYes

Keywords

  • conductance
  • ferroelectric tunneling junction
  • giant piezoelectric resistance
  • phase transition
  • strain

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

Cite this