Strong Asymmetric Carrier Mobility in Monolayer Mn₂In₂Se₅ from First Principles

Materials with strong asymmetric carrier mobility have shown significant advantages in improving the performance and efficiency of semiconductor devices, optoelectronic devices, and thermoelectric devices, especially in two-dimensional van der Waals (vdW) materials that are currently hotly researched. Here, we study the strongly asymmetric carrier mobility by first-principles calculations in a novel two-dimensional vdW material Mn2In2Se5. Similar to the bulk semiconductors property, monolayer Mn2In2Se5 exhibits an antiferromagnetic semiconductor with a Néel temperature of 115 K. Importantly, its electron carrier mobility in both armchair and zigzag transport directions is 2 orders of magnitude higher than that of hole carrier mobility due to the special band structure and effective mass, showing an obvious electron–hole mobility asymmetry. In addition, it was found that as the thickness of the Mn2In2Se5 film increases, the band gap of the system also gradually increases. And under the effect of spin–orbit coupling, the material is more inclined to out-of-plane antiferromagnetic properties, which may be attributed to the structural evolution with increasing film thickness, namely, the elongation of the in-plane Mn–Mn bond lengths and the shortening of the out-of-plane Mn–Mn bond lengths within the same layer. In general, the discovery of strongly asymmetric carrier mobility in monolayer Mn2In2Se5 has a good potential application value in microelectronic devices.