Premium
Changes of Structure and Bonding with Thickness in Chalcogenide Thin Films
Author(s) -
Ronneberger Ider,
Zanolli Zeila,
Wuttig Matthias,
Mazzarello Riccardo
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202001033
Subject(s) - materials science , chalcogenide , ferroelectricity , thin film , condensed matter physics , perovskite (structure) , phase (matter) , electronic structure , ionic bonding , nanotechnology , chemical physics , optoelectronics , crystallography , dielectric , ion , chemistry , physics , organic chemistry , quantum mechanics
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.