论文标题
单层1T-VSE $ _2 $中的多电荷密度波之间可控的相变，通过掺杂和应变工程
Controllable phase transitions between multiple charge density waves in monolayer 1T-VSe$_2$ via doping and strain engineering
论文作者
论文摘要
众所周知，二维（2D）材料具有在其大容量对应物中未发现的新兴特性。最近的实验显示了单层1T-VSE $ _2 $中的$ \ sqrt7 \ times \ sqrt3 $电荷密度波（CDW），与$ 4 \ times 4 \ times 4 \ times 3 $相比。在这里，通过第一原理计算，我们表明多个CDW相竞争单层VSE $ _2 $，其基态可以通过电荷掺杂掺杂和面内双轴菌株来调节。有了兴奋剂，$ \ sqrt7 \ times \ sqrt3 $ cdw of原始vse $ _2 $转移至$ 3 \ times \ sqrt3 $和$ 4 \ times 4 $ phope，后者的后者，其中的大部分集中量为0.2个单位的偏心型浓度，每单位均为0.2个单位。 $ 4 \ times 4 $ CDW阶段也可以在压缩应变下稳定。尽管电子 - 音波耦合在CDW的组中占上风，但我们表明，费米表面嵌套是解释单层1T-VSE $ _2 $中大多数这些过渡的好起点。这些结果使VSE $ _2 $成为基于可控CDW相转换的电子设备的吸引力材料。
Two-dimensional (2D) materials are known to possess emergent properties that are not found in their bulk counterparts. Recent experiments have shown a $\sqrt7 \times \sqrt3$ charge density wave (CDW) in monolayer 1T-VSe$_2$, in contrast to the $4\times 4\times 3$ phase in bulk. Here, via first-principles calculations, we show that multiple CDW phases compete in monolayer VSe$_2$, the ground state of which can be tuned by charge doping and in-plane biaxial strain. With doping, the $\sqrt7 \times \sqrt3$ CDW of the pristine VSe$_2$ transfers to a $3 \times \sqrt3$ and $4\times 4$ phase, the latter of which is a projection of the bulk counterpart, at critical doping concentrations of around 0.2 holes per formula unit and 0.25 electrons per formula unit, respectively. The $4\times 4$ CDW phase can also be stabilized under compressive strain. Although electron-phonon coupling is prevailing in the CDW formation, we show that Fermi surface nesting is a good starting point to explain most of these transitions in monolayer 1T-VSe$_2$. These results make VSe$_2$ an appealing material for electronic devices based on controllable CDW phase transitions.
