Bipolar ferromagnetic semiconductor with large magnetic moment: EuGe₂ monolayer

Two-dimensional (2D) ferromagnetic semiconductors having both ferromagnetism and semi-conductivity hold exciting and promising potentials in spintronic devices at nanoscale. In this work, we explored the electronic and magnetic properties of EuGe₂ monolayer via conducting the first-principles calculations. The electronic band structure shows that EuGe₂ monolayer is a bipolar magnetic semiconductor with a band gap of 0.55 eV based on the Heyd-Scuseria-Ernzerhof (HSE06) method. The magnetic moment and Curie temperature of EuGe₂ monolayer are calculated to be 7 μ_B f.u.⁻¹ and 23 K based on the Heisenberg model. Its perpendicular magnetic anisotropy (PMA) energy is 3.62 meV per formula unit. Additionally, the Curie temperature of EuGe₂ monolayer is increased by 400% under −8% biaxial compressive stain. Our calculation results suggest that EuGe₂ monolayer has potential applications in the field of spintronic devices.