Mapping of the full polarization switching pathways for HfO2 and its implications

• 成果类型: Article
• 署名作者: Hu, Qi; Lv, Shuning; Tsai, Hsiaoyi; Xue, Yufeng; Jing, Xixiang; Lin, Fanrong; Tong, Chuanjia; Cao, Tengfei; Teobaldi, Gilberto; Liu, Li - Min
• 署名单位: Beihang University; Beihang University; Northwestern Polytechnical University; Nanjing University of Aeronautics & Astronautics; Nanjing University of Aeronautics & Astronautics; Central South University; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); STFC Rutherford Appleton Laboratory
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14327
• DOI: 10.1073/pnas.2419685122
• 发表日期: 2025-02-18
• 关键词: total-energy calculations; thin-film; ferroelectricity; phase

摘要

The discovery of ferroelectric phases in HfO2 offers insights into ferroelectricity. Its unique fluorite structure and complex polarization switching pathways exhibit distinct characteristics, challenging conventional analysis methods. Combining group theory and first- principles calculations, we identify numerous unconventional electric polarization switching pathways in HfO2 with energy barriers of 0.32 to 0.57 eV as a function of the different shift in the suboxygen lattices. In total, we identify 47 switching pathways for the orthorhombic phase, corresponding to the left cosets of the Fm3m group with Pca21 group. Contrary to the conception that the tetracoordinated oxygen (OIV) layers are be displaced, leading to polarization switching along any axial direction. The multiple switching pathways in HfO2 result in both 180 degrees polarization reversal and the formation of 90 degrees domains observed experimentally. Calculations show that specific switching pathunder an out- of- plane electric field, thereby maximizing the out- of- plane component of electric field response mechanisms, wake- up, and fatigue in ferroelectrics.