The high K anomaly in ScAlN explained
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arXiv
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| Format: | Preprint |
| Published: |
2026
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| _version_ | 1866911648775667712 |
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| author | Shalish, Ilan |
| author_facet | Shalish, Ilan |
| contents | We resolve the long-standing discrepancy between theoretical material constants and experimental observations of the dielectric response in scandium aluminum nitride (ScAlN). While first-principles calculations of the rigid lattice predict a permittivity of about 11.7, experiments consistently report values near 15. We demonstrate that this "high K" behavior is a manifestation of electromechanical inflation, where the enormous internal electric fields of polar heterostructures induce macroscopic lattice strain via the inverse piezoelectric effect. By applying stress-free mechanical boundary conditions to the coupled equations of state, we derive an analytical relation for the effective permittivity: epsilon_eff=epsilon_33^S + e_33^2/C_33. This model quantitatively accounts for experimental observations across the ScAlN alloy range and defines the fundamental limit of the rigid-lattice approximation in highly polar semiconductors. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2605_03765 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | The high K anomaly in ScAlN explained Shalish, Ilan Materials Science We resolve the long-standing discrepancy between theoretical material constants and experimental observations of the dielectric response in scandium aluminum nitride (ScAlN). While first-principles calculations of the rigid lattice predict a permittivity of about 11.7, experiments consistently report values near 15. We demonstrate that this "high K" behavior is a manifestation of electromechanical inflation, where the enormous internal electric fields of polar heterostructures induce macroscopic lattice strain via the inverse piezoelectric effect. By applying stress-free mechanical boundary conditions to the coupled equations of state, we derive an analytical relation for the effective permittivity: epsilon_eff=epsilon_33^S + e_33^2/C_33. This model quantitatively accounts for experimental observations across the ScAlN alloy range and defines the fundamental limit of the rigid-lattice approximation in highly polar semiconductors. |
| title | The high K anomaly in ScAlN explained |
| topic | Materials Science |
| url | https://arxiv.org/abs/2605.03765 |