Thick Does the Trick: Genesis of Ferroelectricity in 2D GeTe-Rich (GeTe)m(Sb2Te3)n Lamellae

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Stefano Cecchi - , University of Milan - Bicocca, Leibniz Research Association Berlin e. V. (Author)
  • Jamo Momand - , University of Groningen (Author)
  • Daniele Dragoni - , University of Milan - Bicocca (Author)
  • Omar Abou El Kheir - , University of Milan - Bicocca (Author)
  • Federico Fagiani - , Polytechnic University of Milan (Author)
  • Dominik Kriegner - , Chair of Theoretical Solid State Physics, Czech Academy of Sciences (Author)
  • Christian Rinaldi - , Polytechnic University of Milan (Author)
  • Fabrizio Arciprete - , University of Rome Tor Vergata (Author)
  • Vaclav Holý - , Charles University Prague, Masaryk University (Author)
  • Bart J. Kooi - , University of Groningen (Author)
  • Marco Bernasconi - , University of Milan - Bicocca (Author)
  • Raffaella Calarco - , Leibniz Research Association Berlin e. V. , National Research Council of Italy (CNR) (Author)

Abstract

The possibility to engineer (GeTe)m(Sb2Te3)n phase-change materials to co-host ferroelectricity is extremely attractive. The combination of these functionalities holds great technological impact, potentially enabling the design of novel multifunctional devices. Here an experimental and theoretical study of epitaxial (GeTe)m(Sb2Te3)n with GeTe-rich composition is presented. These layered films feature a tunable distribution of (GeTe)m(Sb2Te3)1 blocks of different sizes. Breakthrough evidence of ferroelectric displacement in thick (GeTe)m(Sb2Te3)1 lamellae is provided. The density functional theory calculations suggest the formation of a tilted (GeTe)m slab sandwiched in GeTe-rich blocks. That is, the net ferroelectric polarization is confined almost in-plane, representing an unprecedented case between 2D and bulk ferroelectric materials. The ferroelectric behavior is confirmed by piezoresponse force microscopy and electroresistive measurements. The resilience of the quasi van der Waals character of the films, regardless of their composition, is also demonstrated. Hence, the material developed hereby gathers in a unique 2D platform the phase-change and ferroelectric switching properties, paving the way for the conception of innovative device architectures.

Details

Original languageEnglish
Article number2304785
JournalAdvanced science
Volume11
Issue number1
Publication statusPublished - 5 Jan 2024
Peer-reviewedYes

External IDs

PubMed 37988708

Keywords

Keywords

  • 2D ferroelectrics, density functional theory calculations, molecular beam epitaxy, phase-change materials, van der Waals