Discovery of robust in-plane ferroelectricity in atomic-thick SnTe
Discovery of robust in-plane ferroelectricity in atomic-thick SnTe
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在原子厚度的 SnTe 中发现坚固的面内铁电体
DOI：
10.1126/science.aad8609
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发表时间：
2016-07-15
期刊：
影响因子：
56.9
通讯作者：
Ji, Shuai-Hua
中科院分区：
文献类型：
--
作者：
Chang, Kai;Liu, Junwei;Ji, Shuai-Hua
使铁电材料变薄使其性能更好随着铁电材料变得更薄，其产生永久电极化的温度通常会降低。张等人。制造了高质量的 SnTe 薄膜，与传统观点相反，它的转变温度比块状材料的转变温度高得多（参见 Kooi 和 Noheda 的观点）。即使对于单晶电池薄膜也是如此，而只有稍厚的薄膜在高于室温时才会变成铁电体。这一发现可能使铁电器件小型化成为可能。科学，本期第 14 页。 274；另见 p. 221 扫描隧道显微镜显示出晶格畸变和能带弯曲，这是铁电的特征。小型化铁电器件需要纳米结构中具有高转变温度的稳定铁电性。在这里，我们报告了原子厚碲化锡 (SnTe) 中稳定面内自发极化的发现，低至 1 个晶胞 (UC) 极限。 1-UC SnTe薄膜的铁电转变温度Tc从98开尔文的体值大大提高，达到270开尔文。此外，2-至4-UC SnTe 薄膜在室温下表现出强大的铁电性。这种二维材料的半导体特性和铁电性之间的相互作用可以在非易失性高密度存储器、纳米传感器和电子产品中实现广泛的应用。
Thinning a ferroelectric makes it better As a ferroelectric material becomes thinner, the temperature below which it develops its permanent electrical polarization usually decreases. Chang et al. fabricated high-quality thin films of SnTe that, in contrast to this conventional wisdom, had a considerably higher transition temperature than that of the material in bulk (see the Perspective by Kooi and Noheda). This was true even for single-unit cell films, whereas only slightly thicker films became ferroelectric above room temperature. This finding may enable the miniaturization of ferroelectric devices. Science, this issue p. 274; see also p. 221 Scanning tunneling microscopy indicates lattice distortion and band-bending, characteristic of ferroelectricity. Stable ferroelectricity with high transition temperature in nanostructures is needed for miniaturizing ferroelectric devices. Here, we report the discovery of the stable in-plane spontaneous polarization in atomic-thick tin telluride (SnTe), down to a 1–unit cell (UC) limit. The ferroelectric transition temperature Tc of 1-UC SnTe film is greatly enhanced from the bulk value of 98 kelvin and reaches as high as 270 kelvin. Moreover, 2- to 4-UC SnTe films show robust ferroelectricity at room temperature. The interplay between semiconducting properties and ferroelectricity in this two-dimensional material may enable a wide range of applications in nonvolatile high-density memories, nanosensors, and electronics.