Publication details

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


CECCHI Stefano MOMAND Jamo DRAGONI Daniele OMAR Abou El Kheir FAGIANI Federico KRIEGNER Dominik RINALDI Christian ARCIPRETE Fabrizio HOLÝ Václav KOOI Bart J. BERNASCONI Marco CALARCO Raffaella

Year of publication 2024
Type Article in Periodical
Magazine / Source Advanced Science
MU Faculty or unit

Faculty of Science

Keywords 2D ferroelectrics; van der Waals; molecular beam epitaxy; phase-change materials; density functional theory calculations
Description 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.

You are running an old browser version. We recommend updating your browser to its latest version.

More info