The high electron mobility for spin‐down channel of two‐dimensional spin‐polarized half‐metallic ferromagnetic EuSi2N4 monolayer.

The two‐dimensional (2D) monolayer material MoSi2N4 was successfully synthesized in 2020[Hong et al., Science 369, 670, (2020)], exhibiting a plethora of new phenomena and unusual properties, with good stability at room temperature. However, MA2Z4 family monolayer materials involve primarily transition metal substitutions for M atoms. In order to address the research gap on lanthanide and actinide MA2Z4 materials, this work conducts electronic structure calculations on novel 2D MSi2N4 (M = La, Eu) monolayer materials by employing first‐principles methods and CASTEP. High carrier mobility is discovered in the indirect bandgap semiconductor 2D LaSi2N4 monolayer (~5400 cm2 V−1 s−1) and in the spin (spin‐down channel) carrier mobility of the half‐metallic ferromagnetic EuSi2N4 monolayer (~2800 cm2 V−1 s−1). EuSi2N4 monolayer supplements research on spin carrier mobility in half‐metallic ferromagnetic monolayer materials at room temperature and possesses a magnetic moment of 5 μB, which should not be underestimated. Furthermore, due to the unique electronic band structure of EuSi2N4 monolayer (with the spin‐up channel exhibiting metallic properties and the spin‐down channel exhibiting semiconductor properties), it demonstrates a 100% spin polarization rate, presenting significant potential applications in fields such as magnetic storage, magnetic sensing, and spintronics. [ABSTRACT FROM AUTHOR]