Changes of structure and bonding with thickness in chalcogenide thin films
Ronneberger, Ider (Jülich Aachen Research Alliance)
Zanolli, Zeila (Institut Català de Nanociència i Nanotecnologia)
Wuttig, Matthias (Jülich Aachen Research Alliance)
Mazzarello, Riccardo (Jülich Aachen Research Alliance)

Fecha:	2020
Resumen:	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.
Ayudas:	Ministerio de Economía y Competitividad SEV-2017-0706 Ministerio de Economía y Competitividad RYC-2016-19344 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1506
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	2D materials ; Ferroelectricity ; Metavalent bonding ; Monochalcogenides
Publicado en:	Advanced materials, Vol. 32, issue 29 (July 2020) , art. 2001033, ISSN 1521-4095

DOI: 10.1002/adma.202001033

10 p, 3.3 MB

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Documentos de investigación > Documentos de los grupos de investigación de la UAB > Centros y grupos de investigación (producción científica) > Ciencias > Institut Català de Nanociència i Nanotecnologia (ICN2)
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