All‐Optical Detection of Periodic Structure of Chalcogenide Superlattice Using Coherent Folded Acoustic Phonons (Phys. Status Solidi RRL 9/2018). Issue 9 (9th September 2018)

• Record Type: Journal Article
• Authors: Suzuki, Takara; Saito, Yuta; Fons, Paul; Kolobov, Alexander V.; Tominaga, Junji; Hase, Muneaki
• Is Part Of: Physica status solidi. Volume 12:Issue 9(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-09
• Subjects: Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201870328
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : Chalcogenide superlattices (SLs) consist of the alternate stacking of GeTe and Sb2 Te3 layers. The structure can act as a 3D topological insulator depending on the constituent layer thicknesses, making the design of the SL period a central issue for advancing chalcogenide SLs as potential candidates for spin devices as well as for the optimization of the current generation of phase‐change memory devices. In article no.1800246, Muneaki Hase and co‐workers explore the periodic structure of chalcogenide SLs by observing coherent folded longitudinal acoustic (FLA) phonons excited by femtosecond laser pulse irradiation via transient reflectivity change. The FLA phonons propagate through the SL structure. The peak frequency of the FLA modes was observed to change upon variation of the thickness of the GeTe layer, which was well reproduced by means of an elastic continuum model. This all‐optical technique based on the observation of coherent FLA modes offers a non‐destructive characterization method for superlattice structures with atomic resolution.