Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf0.5Zr0.5O2 thin films

Pavan Nukala*, Yingfen Wei, Vincent de Haas, Qikai Guo, Jordi Antoja-Lleonart, Beatriz Noheda*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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The unconventional Si-compatible ferroelectricity in hafnia-based systems, which becomes robust only at nanoscopic sizes, has attracted a lot of interest. While a metastable polar orthorhombic (o-) phase (Pca2(1)) is widely regarded as the responsible phase for ferroelectricity, a higher energy polar rhombohedral (r-) phase is recently reported on epitaxial HfZrO4 (HZO) films grown on (001) SrTiO3 (R3m or R3), (0001) GaN (R3), and Si (111). Armed with results on these systems, here we report a systematic study leading toward identifying comprehensive global trends for stabilizing r-phase polymorphs in epitaxially grown HZO thin films (6 nm) on various substrates (perovskites, hexagonal and Si).

Original languageEnglish
Pages (from-to)148-163
Number of pages16
Issue number1
Publication statusPublished - 9-Dec-2020


  • Polar rhombohedral phase
  • epitaxial (111) Hf0 .5Zr0.5O2 thin-films
  • compressive strain

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