Layered ZrGeTe4is a new type of ternary anisotropic semiconductor material. The strong in-plane anisotropy may give us another degree of freedom for controlling electrical and optical properties and designing advanced nanodevices. Using both first-principles calculations and Raman spectroscopy, physical properties such as band structure, phonon vibration, and carrier mobility of layered ZrGeTe4from bulk to monolayer were investigated. The bulk and few-layer ZrGeTe4are predicted as indirect bandgap semiconductors, but the monolayer ZrGeTe4turns out to be a direct band gap semiconductor with moderate value of 1.08 eV. Detail calculations reveal that the van der Waals (vdW) interaction is the main reason of causing the transition from indirect band gap to direct one. Phonon calculations and Raman spectroscopy together demonstrate that the layered ZrGeTe4is mechanically stable and anisotropic. In orders of magnitude, the predicted carrier mobility of ZrGeTe4(∽103cm2V-1s-1) is between that of graphene (∽105) and MoS2(∽102), and the anisotropy of electronic mobility is similar to that of black phosphorus (BP), while hole mobility varies with the numbers of layers.

中文翻译：

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二维半导体 ZrGeTe _{4 的}强各向异性和层相关载流子迁移率

层状ZrGeTe4是一种新型的三元各向异性半导体材料。强大的面内各向异性可能为我们控制电学和光学特性以及设计先进的纳米器件提供了另一个自由度。使用第一性原理计算和拉曼光谱，研究了层状 ZrGeTe4 从块体到单层的物理性质，如能带结构、声子振动和载流子迁移率。块状和少层 ZrGeTe4 被预测为间接带隙半导体，但单层 ZrGeTe4 被证明是具有中等值 1.08 eV 的直接带隙半导体。详细计算表明，范德华 (vdW) 相互作用是导致从间接带隙过渡到直接带隙的主要原因。声子计算和拉曼光谱共同证明层状 ZrGeTe4 具有机械稳定性和各向异性。在数量级上，ZrGeTe4(∽103cm2V-1s-1)的预测载流子迁移率介于石墨烯(∽105)和MoS2(∽102)之间，电子迁移率的各向异性与黑磷(BP )，而空穴迁移率随层数而变化。