Doping-induced Polyamorphic Transitions in Fluorite Oxides
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arXiv
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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866918067983876096 |
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| author | Yang, Hao Luan, Qiaotong Zhang, Qing Yue, Yuhao Xu, Yawen Liu, Xiaohui Wen, Zheng Sun, Zhaoru |
| author_facet | Yang, Hao Luan, Qiaotong Zhang, Qing Yue, Yuhao Xu, Yawen Liu, Xiaohui Wen, Zheng Sun, Zhaoru |
| contents | Fluorite oxides such as HfO$_2$ exhibit rich and tunable phase behavior, making them promising candidates for next generation electronic devices. A key challenge is to design amorphous HfO$_2$-based high-$k$ materials with both structural and performance stability. Here, using molecular dynamics simulations supported by experimental measurements, we reveal that Ba doping stimulates a polyamorphic transition in HfO$_2$, yielding a semi-ordered amorphous (SA) phase characterized by disordered oxygens embedded within an ordered metal sublattice. We find that this phase arises from degenerate short-range symmetry breaking modes, consistent with Pauling's parsimony rule. Notably, the SA structure is thermodynamically stable and displays a wider bandgap and higher dielectric constant than conventional random-packing amorphous structure, owing to suppressed subgap states and increased Born effective charges. We further demonstrate that this structural motif generalizes to Ba-, Sr-, and Ca-doped HfO$_2$ and ZrO$_2$, establishing a broadly applicable strategy for designing high-performance amorphous dielectrics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_18333 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Doping-induced Polyamorphic Transitions in Fluorite Oxides Yang, Hao Luan, Qiaotong Zhang, Qing Yue, Yuhao Xu, Yawen Liu, Xiaohui Wen, Zheng Sun, Zhaoru Materials Science Statistical Mechanics Fluorite oxides such as HfO$_2$ exhibit rich and tunable phase behavior, making them promising candidates for next generation electronic devices. A key challenge is to design amorphous HfO$_2$-based high-$k$ materials with both structural and performance stability. Here, using molecular dynamics simulations supported by experimental measurements, we reveal that Ba doping stimulates a polyamorphic transition in HfO$_2$, yielding a semi-ordered amorphous (SA) phase characterized by disordered oxygens embedded within an ordered metal sublattice. We find that this phase arises from degenerate short-range symmetry breaking modes, consistent with Pauling's parsimony rule. Notably, the SA structure is thermodynamically stable and displays a wider bandgap and higher dielectric constant than conventional random-packing amorphous structure, owing to suppressed subgap states and increased Born effective charges. We further demonstrate that this structural motif generalizes to Ba-, Sr-, and Ca-doped HfO$_2$ and ZrO$_2$, establishing a broadly applicable strategy for designing high-performance amorphous dielectrics. |
| title | Doping-induced Polyamorphic Transitions in Fluorite Oxides |
| topic | Materials Science Statistical Mechanics |
| url | https://arxiv.org/abs/2506.18333 |