Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

The room-temperature intrinsic ferromagnetism of monolayer VSe2 with a van der Waals gap provides an exciting opportunity for both the fundamental studies and future low-dimensional spintronic devices. By applying biaxial strain, the tunable electronic, magnetic, and phonon transport properties of the VSe2 monolayer are systematically investigated via first-principle calculations. With in-plane easy magnetization axis, the VSe2 monolayer is always a robust room-temperature ferromagnetic semiconductor in the strain range from −2 to 4%. According to the second-order perturbation theory of spin-orbital coupling, magnetic anisotropy energy is mainly contributed by the interaction between V- $$d_{{xy}}$$ orbital and V- $$d_{{x² - y² }}$$ orbital. The Curie temperature increases significantly with increasing biaxial strain, from 303 to 469 K. In the meantime, room-temperature lattice thermal conductivity is only 0.682 Wm−1 K−1 and exhibits strong strain dependence. The weakened anharmonic three-phonon scattering rate due to the tradeoff between the number and the strength of scattering channel largely compensates for the influence of the reduced phonon group velocity, causing a monotonous increase in the lattice thermal conductivity with the strain changing. Moreover, the lattice thermal conductivity can be reduced further by limiting the size of monolayer under tensile strain, due to the enhanced size dependence of the thermal conductivity.