Two-dimensional chromium pnictides CrX (X =P, As, Sb): Half-metallic ferromagnets with high Curie temperature

Using first-principles calculations, we demonstrate that hexagonal monolayers of chromium pnictides CrX(X=P, As, Sb) are ferromagnetically ordered systems with the Curie temperature well above 300 K. All three systems are found to be dynamically stable, having no anomalies in the phonon spectrum. Electronic structure calculations show that CrX are half-metals in a wide energy range, which make them perfect spin polarizers and candidates for observing anomalous Hall effect. Our predictions are robust with respect to external dielectric screening induced, for example, by substrates or encapsulation.