Over the last few years, ab initio methods have become an increasingly popular tool to evaluate intrinsic carrier transport properties in 2D semiconductors. The lack of experimental information, and the progress made in the development of DFT tools to evaluate electronic band structures, phonon dispersions, and electron–phonon scattering matrix-elements, have made them a favored choice. However, a large discrepancy is observed in the literature among the ab initio calculated carrier mobility in 2D semiconductors. Some of the discrepancies are a result of the physical approximations made in calculating the electron–phonon coupling constants and the carrier mobility. These approximations can be avoided by using a sophisticated transport model. However, despite using appropriate transport models, the uncertainty in the reported carrier mobility is still quite large in some materials. The major differences observed between these refined model calculations are the ‘flavors’ of DFT (exchange-correlation functional, pseudopotential, and the effect of spin-orbit coupling) used. Here, considering several monolayer 2H-TMDs as examples, we calculate the low- and high-field transport properties using different ‘flavors’ of DFT, and calculate a range for the electron mobility values. We observe that in some materials the values differ by orders of magnitude (For example, in monolayer WS₂ the electron low-field mobility varies between 37 \(\hbox {cm}^{2}/(\hbox {V}\,\hbox {s}\)) and 767 \(\hbox {cm}^{2}/(\hbox {V}\,\hbox {s}\))). We analyze critically these discrepancies, and try to understand the limitations of the current ab initio methods in calculating carrier transport properties.

在过去的几年中，从头算方法已经成为评估2D半导体中固有载流子传输特性的一种越来越流行的工具。缺乏实验信息，以及在开发DFT工具以评估电子能带结构，声子色散和电子-声子散射矩阵元素方面取得的进展，使它们成为首选的选择。然而，在文献中观察到了从头算出的2D半导体载流子迁移率之间的巨大差异。一些差异是计算电子-声子耦合常数和载流子迁移率时物理近似的结果。通过使用复杂的运输模型可以避免这些近似。但是，尽管使用了适当的运输模型，在某些材料中，所报告的载流子迁移率的不确定性仍然很大。在这些改进的模型计算之间观察到的主要差异是所使用的DFT的“风味”（交换相关函数，伪势以及自旋轨道耦合的影响）。在这里，以几个单层2H-TMD为例，我们使用DFT的不同“风味”来计算低场和高场传输性质，并计算电子迁移率值的范围。我们观察到某些材料中的值相差几个数量级（例如，在单层WS中 以几个单层2H-TMD为例，我们使用DFT的不同“风味”计算低场和高场传输性能，并计算电子迁移率值的范围。我们观察到某些材料中的值相差几个数量级（例如，在单层WS中 以几个单层2H-TMD为例，我们使用DFT的不同“风味”计算低场和高场传输性能，并计算电子迁移率值的范围。我们观察到某些材料中的值相差几个数量级（例如，在单层WS中₂电子低场迁移率在37 \（\ hbox {cm} ^ {2} /（\ hbox {V} \，\ hbox {s} \））和767 \（\ hbox {cm} ^ {2 } /（\ hbox {V} \，\ hbox {s} \）））。我们批判性地分析了这些差异，并试图了解当前从头算方法在计算载流子传输特性方面的局限性。