Kinetically stabilized ferroelectricity in bulk single-crystalline HfO2:Y

Xianghan Xu, Fei Ting Huang, Yubo Qi, Sobhit Singh, Karin M. Rabe, Dimuthu Obeysekera, Junjie Yang, Ming Wen Chu, Sang Wook Cheong

Research output: Contribution to journalArticlepeer-review

147 Scopus citations

Abstract

HfO2, a simple binary oxide, exhibits ultra-scalable ferroelectricity integrable into silicon technology. This material has a polymorphic nature, with the polar orthorhombic (Pbc21) form in ultrathin films regarded as the plausible cause of ferroelectricity but thought not to be attainable in bulk crystals. Here, using a state-of-the-art laser-diode-heated floating zone technique, we report the Pbc21 phase and ferroelectricity in bulk single-crystalline HfO2:Y as well as the presence of the antipolar Pbca phase at different Y concentrations. Neutron diffraction and atomic imaging demonstrate (anti)polar crystallographic signatures and abundant 90°/180° ferroelectric domains in addition to switchable polarization with negligible wake-up effects. Density-functional-theory calculations indicate that the yttrium doping and rapid cooling are the key factors for stabilization of the desired phase in bulk. Our observations provide insights into the polymorphic nature and phase control of HfO2, remove the upper size limit for ferroelectricity and suggest directions towards next-generation ferroelectric devices.

Original languageEnglish (US)
Pages (from-to)826-832
Number of pages7
JournalNature Materials
Volume20
Issue number6
DOIs
StatePublished - Jun 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature Limited.

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