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| Main Authors: | , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.00307 |
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| _version_ | 1866914028812500992 |
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| author | Gong, Jiayi Zhang, Chuanyu Hu, Wenjie Zhou, Jin-Jian |
| author_facet | Gong, Jiayi Zhang, Chuanyu Hu, Wenjie Zhou, Jin-Jian |
| contents | Alkaline earth stannates have emerged as promising transparent conducting oxides due to their wide band gaps and high room-temperature electron mobilities. Among them, CaSnO$_3$ possesses the widest band gap, yet reported mobilities vary widely and are highly sample-dependent, leaving its intrinsic limit unclear. Here, we present ab initio calculations of electron mobility in CaSnO$_3$ across a range of temperatures and doping levels, using state-of-the-art methods that explicitly account for free-carrier screening in electron-phonon interactions. We identify the dominant limiting mechanism to be the long-range longitudinal optical phonon scattering, which is significantly suppressed at high doping due to free-carrier screening, leading to enhanced phonon-limited mobility. While ionized impurity scattering emerges as a competing mechanism at carrier concentrations up to ~10$^{20}$ cm$^{-3}$, the phonon scattering reduction dominates, yielding a net mobility increase with predicted room-temperature values reaching about twice the highest experimental report. Our work highlights the substantial untapped conductivity in CaSnO$_3$, establishing it as a compelling ultrawide bandgap semiconductor for transparent and high-power electronic applications. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_00307 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Free-carrier screening unlocks high electron mobility in ultrawide bandgap semiconductor CaSnO$_3$ Gong, Jiayi Zhang, Chuanyu Hu, Wenjie Zhou, Jin-Jian Materials Science Alkaline earth stannates have emerged as promising transparent conducting oxides due to their wide band gaps and high room-temperature electron mobilities. Among them, CaSnO$_3$ possesses the widest band gap, yet reported mobilities vary widely and are highly sample-dependent, leaving its intrinsic limit unclear. Here, we present ab initio calculations of electron mobility in CaSnO$_3$ across a range of temperatures and doping levels, using state-of-the-art methods that explicitly account for free-carrier screening in electron-phonon interactions. We identify the dominant limiting mechanism to be the long-range longitudinal optical phonon scattering, which is significantly suppressed at high doping due to free-carrier screening, leading to enhanced phonon-limited mobility. While ionized impurity scattering emerges as a competing mechanism at carrier concentrations up to ~10$^{20}$ cm$^{-3}$, the phonon scattering reduction dominates, yielding a net mobility increase with predicted room-temperature values reaching about twice the highest experimental report. Our work highlights the substantial untapped conductivity in CaSnO$_3$, establishing it as a compelling ultrawide bandgap semiconductor for transparent and high-power electronic applications. |
| title | Free-carrier screening unlocks high electron mobility in ultrawide bandgap semiconductor CaSnO$_3$ |
| topic | Materials Science |
| url | https://arxiv.org/abs/2509.00307 |