Ferroelectricity and Phase Transitions in Monolayer Group-IV Monochalcogenides
Ferroelectricity and Phase Transitions in Monolayer Group-IV Monochalcogenides
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DOI：
10.1103/physrevlett.117.097601
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发表时间：
2016-08-23
影响因子：
8.6
通讯作者：
Yang, Li
中科院分区：
文献类型：
--
作者：
Fei, Ruixiang;Kang, Wei;Yang, Li
铁电性通常随着材料减薄到某个临界值以下而逐渐消失。我们揭示了独特的离子电位非调和性可以诱导单层iv族单硫属化合物MX （M = Ge, Sn; X = S, Se）的自发面内电极化和铁电性。成功地从参数化的能量空间中提取了一个有效的哈密顿量，使研究单原子层中的铁电相变成为可能。这些材料的铁电性很强，相应的居里温度高于室温，这使得它们有望实现广泛关注的超薄铁电器件。我们进一步提供了相图并预测了其他潜在的二维铁电材料。
Ferroelectricity usually fades away as materials are thinned down below a critical value. We reveal that the unique ionic-potential anharmonicity can induce spontaneous in-plane electrical polarization and ferroelectricity in monolayer group-IV monochalcogenides MX (M = Ge, Sn; X = S, Se). An effective Hamiltonian has been successfully extracted from the parametrized energy space, making it possible to study the ferroelectric phase transitions in a single-atom layer. The ferroelectricity in these materials is found to be robust and the corresponding Curie temperatures are higher than room temperature, making them promising for realizing ultrathin ferroelectric devices of broad interest. We further provide the phase diagram and predict other potentially two-dimensional ferroelectric materials.