  Two-dimensional materials have been gaining great attention as they displayed
a broad series of electronic properties that ranging from superconductivity to
topology. Among them, those which possess magnetism are most desirable,
enabling us to manipulate charge and spin simultaneously. Here, based on
first-principles calculation, we demonstrate monolayer chromium iodide arsenide
(CrIAs), an undiscovered stable two-dimensional material, is an intrinsic
ferromagnetic semiconductor with out-of-plane spin magnetization. The indirect
bandgaps are predicted to be 0.32 eV for majority spin and 3.31 eV for minority
spin, large enough to preserve semiconducting features at room temperature. Its
Curie temperature, estimated by Heisenberg model with magnetic anisotropic
energy using Monte Carlo method, is as high as 655 K that well above the room
temperature, owing to strong direct exchange interaction between chromium d and
iodine p orbitals. This work offers the affirmative answer of whether there
exists two-dimensional ferromagnetic semiconductor at room temperature. And the
practical realization of quantum spintronic devices, which have been suppressed
because of lacking suitable room temperature magnetic materials, would embrace
a great opportunity.
