Functionalized two-dimensional materials with multiferroicity are highly desired to be next-generation electronic devices. Here we theoretically predict a family of Janus vanadium dichalcogenides VXX’ (X/X’ = S, Se, Te) monolayers with multiferroic properties, combing ferromagnetism, ferroelasticity and piezoelectricity. Due to the unpaired electrons on the V atom, the Janus VXX’ monolayers have intrinsic long-range ferromagnetic orders. Particularly, the Curie temperature of 1T-VSeTe monolayer is up to 100 K, which is greatly higher than 2D 1T-VSe 2 and 1T-VTe 2 . Furthermore, the six Janus VXX’ monolayers have similar crater-like ferroelastic switching curves. Compared to black phosphorus, 2H-VSSe monolayer has the similar ferroelastic switching signal and 4 times lower energy barrier. In addition, the out-of-plane piezoelectricity induced by the structure asymmetry in the vertical direction gives the 2H-VXX’ monolayers the potential to be piezoelectric mate...

中文翻译：

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多功能Janus钒二硫属化物中内置电场作用下居里温度的提高

具有多铁性的功能化二维材料是下一代电子设备。在这里，我们从理论上预测了具有多铁性，结合铁磁性，铁弹性和压电性的Janus钒二硫化氢VXX'（X / X'= S，Se，Te）单层族。由于V原子上不成对的电子，Janus VXX'单层具有固有的远距离铁磁有序。特别地，1T-VSeTe单层的居里温度高达100 K，这大大高于2D 1T-VSe 2和1T-VTe 2。此外，六个Janus VXX'单层具有类似的火山口状的铁弹性转换曲线。与黑磷相比，2H-VSSe单层具有类似的铁弹性开关信号，并且能垒低4倍。此外，