Growth and decay of a two‐dimensional oxide quasicrystal: High‐temperature in situ microscopy. Issue 1 (7th November 2016)

• Record Type: Journal Article
• Authors: Förster, Stefan; Flege, Jan Ingo; Zollner, Eva Maria; Schumann, Florian Otto; Hammer, Rene; Bayat, Alireza; Schindler, Karl‐Michael; Falta, Jens; Widdra, Wolf
• Is Part Of: Annalen der Physik. Volume 529:Issue 1/2(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-11-07
• Subjects: Oxide quasicrystal -- 2D materials -- barium titanate -- LEEM -- XPS; Physics -- Periodicals; Chemistry -- Periodicals; 530.05
• DOI: 10.1002/andp.201600250
• Languages: English
• ISSNs: 0003-3804

Abstract

Abstract : Recently, the first two‐dimensional oxide quasicrystal in condensed matter has been discovered. The formation process of this unique structure is monitored in situ using low‐energy electron microscopy on the nanoscale. The structure evolves from an amorphous wetting layer at high temperatures in UHV and can reversibly be transformed into a 3D island structure by changing the oxygen chemical potential. The full process is monitored in real time. Abstract : The recently discovered two‐dimensional oxide quasicrystal (OQC) derived from BaTiO3 on Pt(111) is the first material in which a spontaneous formation of an aperiodic structure at the interface to a periodic support has been observed. Herein, we report in situ low‐energy electron microscopy (LEEM) studies on the fundamental processes involved in the OQC growth. The OQC formation proceeds in two steps via of an amorphous two‐dimensional wetting layer. At 1170 K the long‐range aperiodic order of the OQC develops. Annealing in O2 induces the reverse process, the conversion of the OQC into BaTiO3 islands and bare Pt(111), which has been monitored by in situ LEEM. A quantitative analysis of the temporal decay of the OQC shows that oxygen adsorption on bare Pt patches is the rate limiting step of this dewetting process.