Electric-field-induced annihilation of localized gap defect states in amorphous phase-change memory materials

Konstantinos Konstantinou, Felix C. Mocanu, Jaakko Akola, Stephen R. Elliott

Tutkimustuotos: ArticleScientificvertaisarvioitu

3 Lataukset (Pure)

Abstrakti

Structural relaxation of amorphous phase-change-memory materials has been attributed to defect-state annihilation from the band gap, leading to a time-dependent drift in the electrical resistance, which hinders the development of multi-level memory devices with increased data-storage density. In this computational study, homogeneous electric fields have been applied, by utilizing a Berry-phase approach with hybrid-density-functional-theory simulations, to ascertain their effect on the atomic and electronic structures associated with the mid-gap states in models of the prototypical glassy phase-change material, Ge2Sb2Te5. Above a threshold value, electric fields remove spatially localized defects from the band gap and transform them into delocalized conduction-band-edge electronic states. A lowering of the nearest-neighbor coordination of Ge atoms in the local environment of the defect-host motif is observed, accompanied by a breaking of 4-fold rings. This engineered structural relaxation, through electric-field tuning of electronic and geometric properties in the amorphous phase, paves the way to the design of optimized glasses.

AlkuperäiskieliEnglanti
Artikkeli117465
Sivumäärä11
JulkaisuActa Materialia
Vuosikerta223
Varhainen verkossa julkaisun päivämäärä6 marrask. 2021
DOI - pysyväislinkit
TilaJulkaistu - 15 tammik. 2022
OKM-julkaisutyyppiA1 Alkuperäisartikkeli

Julkaisufoorumi-taso

  • Jufo-taso 3

!!ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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