The quantum anomalous Hall effect and strong robustness in two-dimensional p-state Dirac half-metals Y3X2 (Y = Li, Na; X = Se, Te)

Abstract

Based on first-principles calculations, we have predicted a novel group of 2D p-state Dirac half-metal (DHM) materials, Y₃X₂ (Y = Li, Na; X = Se, Te) monolayers. All the monolayers exhibit intrinsic ferromagnetism. Among them, Li₃Te₂ and Na₃Se₂ open topologically nontrivial band gaps of 4.0 meV and 5.0 meV considering spin–orbit coupling (SOC), respectively. The Curie temperature of Li₃Te₂ is 355 K. The non-zero Chern number and the presence of edge states further confirm that the Li₃Te₂ monolayer is a room-temperature ferromagnetic material and a quantum anomalous Hall (QAH) insulator. Additionally, it is found that Y₃X₂ (Y = Li, Na; X = Se, Te) monolayers exhibit strong robustness against strain and electric fields. Finally, we have proposed the growth of Y₃X₂ (Y = Li, Na; X = Se, Te) monolayers on h-BN substrates, which shows promise for experimental synthesis. Our research indicates that Y₃X₂ (Y = Li, Na; X = Se, Te) monolayers exhibit strong robustness as DHMs, showcasing significant potential for realizing the intrinsic quantum anomalous Hall effect (QAHE).