Polar phase transitions in heteroepitaxial stabilized La0.5Y0.5AlO3 thin films

Shenghua Liu, Chunfeng Zhang, Mengya Zhu, Qian He, Jak Chakhalian, Xiaoran Liu, Albina Borisevich, Xiaoyong Wang, Min Xiao

Research output: Contribution to journalArticle


We report on the fabrication of epitaxial La0.5Y0.5AlO3 ultrathin films on (001) LaAlO3 substrates. Structural characterizations by scanning transmission electron microscopy and x-ray diffraction confirm the high quality of the film with a - b + c - AlO6 octahedral tilt pattern. Unlike either of the nonpolar parent compound, LaAlO3 and YAlO3, second harmonic generation measurements on the thin films suggest a nonpolar-polar phase transition at T c near 500 K, and a polar-polar phase transition at T a near 160 K. By fitting the angular dependence of the second harmonic intensities, we further propose that the two polar structures can be assigned to the Pmc2 1 and Pmn2 1 space group, while the high temperature nonpolar structure belongs to the Pbnm space group.

Original languageEnglish (US)
Article number405401
JournalJournal of Physics Condensed Matter
Issue number40
Publication statusPublished - Sep 1 2017


All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics


  • eptaxial growth
  • polar structure
  • provskite oxide

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