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arXiv · 2407.01914

Switchable Ferroelectricity in Subnano Silicon Thin Films

Hongyu Yu·Shihan deng·Muting Xie·Yuwen Zhang·Xizhi Shi·Jianxin Zhong·Chaoyu He·Hongjun Xiang
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Abstract

Recent advancements underscore the critical need to develop ferroelectric materials compatible with silicon. We systematically explore possible ferroelectric silicon quantum films and discover a low-energy variant (hex-OR-2*2-P) with energy just 1 meV/atom above the ground state (hex-OR-2*2). Both hex-OR-2*2 and hex-OR-2*2-P are confirmed to be dynamically and mechanically stable semiconductors with indirect gaps of 1.323 eV and 1.311 eV, respectively. The ferroelectric hex-OR-2*2-P exhibits remarkable in-plane spontaneous polarization up to 120 Pc/m and is protected by a potential barrier (13.33 meV/atom) from spontaneously transitioning to hex-OR-22. To simulate the switching ferroelectricity in electric fields of the single-element silicon bilayer, we develop a method that simultaneously learns interatomic potentials and Born effective charges (BEC) in a single equivariant model with a physically informed loss. Our method demonstrates good performance on several ferroelectrics. Simulations of hex-OR-2*2-P silicon suggest a depolarization temperature of approximately 300 K and a coercive field of about 0.05 V/{\AA}. These results indicate that silicon-based ferroelectric devices are feasible, and the ground state phase of the silicon bilayer (hex-OR-2*2) is an ideal system. Our findings highlight the promise of pure silicon ferroelectric materials for future experimental synthesis and applications in memory devices, sensors, and energy converters.

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Hongyu Yu, Shihan deng, Muting Xie, Yuwen Zhang, Xizhi Shi, Jianxin Zhong, Chaoyu He, Hongjun Xiang. 2024-07-02. Switchable Ferroelectricity in Subnano Silicon Thin Films. https://arxiv.org/abs/2407.01914

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