Characterization of the ScAlMgO4 cleaving layer by X-ray crystal truncation rod scattering

Takashi Hanada, Hiroo Tajiri, Osami Sakata, Tsuguo Fukuda, Takashi Matsuoka

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


ScAlMgO4 - easily cleaved in c-plane - forms a natural superlattice structure of a ScO2 layer and two Al0.5Mg0.5O layers stacking along c-axis. ScAlMgO4 is one of the RAMO4-type layered multicomponent oxides and a promising lattice-matching substrate material for InGaN and ZnO. Identification of the topmost layer and the surface atomic structure of the cleaved ScAlMgO4 (0001) are investigated by the X-ray crystal truncation rod scattering method. It is confirmed that ScAlMgO4 is cleaved between the two Al0.5Mg0.5O layers. The two parts separated at this interlayer are inversion symmetric to each other and without surface charge. This prevents parallel-plate-capacitor-like electrostatic force during the cleavage. Two different mechanisms are proposed for the two types of cleavage caused by the impact of a wedge and by the in-plane stress due to an overgrown thick GaN film. It is also revealed that about 10%-20% of the topmost O atoms are desorbed during a surface cleaning at 600 °C in ultra-high vacuum. Surface observations using reflection high-energy electron diffraction are possible only after the high-temperature cleaning because the electrical conduction caused by the oxygen deficiency prevents the charge-up of the insulating sample.

Original languageEnglish
Article number205305
JournalJournal of Applied Physics
Issue number20
Publication statusPublished - 2018 May 28

ASJC Scopus subject areas

  • Physics and Astronomy(all)


Dive into the research topics of 'Characterization of the ScAlMgO4 cleaving layer by X-ray crystal truncation rod scattering'. Together they form a unique fingerprint.

Cite this