Room-temperature ferroelectricity in MoTe<sub>2</sub> down to the atomic monolayer limit.

Yuan, Shuoguo; Luo, Xin; Chan, Hung Lit; Xiao, Chengcheng; Dai, Yawei; Xie, Maohai; Hao, Jianhua · Nat Commun · 2019

basic_science · Level V

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Abstract

Ferroelectrics allow for a wide range of intriguing applications. However, maintaining ferroelectricity has been hampered by intrinsic depolarization effects. Here, by combining first-principles calculations and experimental studies, we report on the discovery of robust room-temperature out-of-plane ferroelectricity which is realized in the thinnest monolayer MoTe<sub>2</sub> with unexploited distorted 1T (d1T) phase. The origin of the ferroelectricity in d1T-MoTe<sub>2</sub> results from the spontaneous symmetry breaking due to the relative atomic displacements of Mo atoms and Te atoms. Furthermore, a large ON/OFF resistance ratio is achieved in ferroelectric devices composed of MoTe<sub>2</sub>-based van der Waals heterostructure. Our work demonstrates that ferroelectricity can exist in two-dimensional layered material down to the atomic monolayer limit, which can result in new functionalities and achieve unexpected applications in atomic-scale electronic devices.