Room-temperature ferroelectricity in MoTe2 down to the atomic monolayer limit

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 2 with unexploited distorted 1T ( d 1T) phase. The origin of the ferroelectricity in d 1T-MoTe 2 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 2 -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.

Recent Progress in Two‐Dimensional Ferroelectric Materials

“…In 2019, Yuan et al reported an experimental observation of room temperature ferroelectricity in monolayer d1T-MoTe 2 . [120] They used X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy to confirm the elemental composition and compare the phase differences, as shown in Figure 11a. Then, the atomic structure differences in the 2H and d1T phases were illustrated by high-resolution transmission electron microscopy (HRTEM), where some Te vacancies were observed in the d1T phase (Figure 11b,c).…”

“…Except for employing van der Waals ferroelectric materials, exploring IP ferroelectricity in compounds is also a good choice for obtaining nanoscale Reproduced with permission. [120] Copyright 2019, Nature Publishing Group. www.advelectronicmat.de ferroelectrics.…”

Efficient Energy Conversion and Storage Based on Robust Fluoride‐Free Self‐Assembled 1D Niobium Carbide in 3D Nanowire Network

“…Compared to other reported double layered MXenes, Nb 2 C possesses an excellent conductivity with almost zero or small bandgap that also furnishes its prominence which is distinct from traditional 2D materials. [ 10,19,20 ] In the merit of good biocompatibility, near‐infrared (NIR) adsorption, and high photothermal conversion performance, [ 21 ] Nb 2 C is chosen as a promising candidate for both in vitro and in vivo photothermal/bio‐detection applications. [ 6,7 ] On the other hand, Nb 2 C, which exhibits a good ion intake ability, is vastly used as a cathode for metal ion battery.…”

Selective phase growth and precise-layer control in MoTe2

“…1b) is a Weyl semi-metal in the bulk form. Since the discovery of topological superconductivity and large magnetoresistance in this compound it has been the subject of comprehensive fundamental research [11][12][13][14] . In addition, 1T′-MoTe 2 has been highlighted as an emerging energy material with applications ranging from photovoltaic cells to hydrogen evolution catalysis [15][16][17] .…”