Changes of Structure and Bonding with Thickness in Chalcogenide Thin Films

Ider Ronneberger, Zeila Zanolli, Matthias Wuttig, Riccardo Mazzarello*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Extreme miniaturization is known to be detrimental for certain properties, such as ferroelectricity in perovskite oxide films below a critical thickness. Remarkably, few-layer crystalline films of monochalcogenides display robust in-plane ferroelectricity with potential applications in nanoelectronics. These applications critically depend on the electronic properties and the nature of bonding in the 2D limit. A fundamental open question is thus to what extent bulk properties persist in thin films. Here, this question is addressed by a first-principles study of the structural, electronic, and ferroelectric properties of selected monochalcogenides (GeSe, GeTe, SnSe, and SnTe) as a function of film thickness up to 18 bilayers. While in selenides a few bilayers are sufficient to recover the bulk behavior, the Te-based compounds deviate strongly from the bulk, irrespective of the slab thickness. These results are explained in terms of depolarizing fields in Te-based slabs and the different nature of the chemical bond in selenides and tellurides. It is shown that GeTe and SnTe slabs inherit metavalent bonding of the bulk phase, despite structural and electronic properties being strongly modified in thin films. This understanding of the nature of bonding in few-layers structures offers a powerful tool to tune materials properties for applications in information technology.

Original languageEnglish
Article number2001033
Number of pages10
JournalAdvanced Materials
Volume32
Issue number29
DOIs
Publication statusPublished - 23 Jul 2020
Externally publishedYes

Keywords

  • 2D materials
  • ferroelectricity
  • metavalent bonding
  • monochalcogenides

Fingerprint

Dive into the research topics of 'Changes of Structure and Bonding with Thickness in Chalcogenide Thin Films'. Together they form a unique fingerprint.

Cite this