  Janus materials possess extraordinary physical, chemical, and mechanical
properties caused by symmetry breaking. Here, the mechanic properties,
electronic structure, magnetic properties, and optical properties of Janus
Cr$_2$TeX (X= P, As, Sb) monolayers are systematically investigated by the
density functional theory. Janus Cr$_2$TeP, Cr$_2$TeAs, and Cr$_2$TeSb are
intrinsic ferromagnetic (FM) half-metals with wide spin gaps and half-metallic
gaps. Monte Carlo simulations based on the Heisenberg model estimate the Curie
temperature (\emph{T}$_c$) of these monolayers are about 583, 608, and 597 K,
respectively. Additionally, it is found that Cr$_2$TeX (X= P, As, Sb)
monolayers still exhibit FM half-metallic properties under biaxial strain from
-6% to 6%. At last, the Cr$_2$TeP monolayer has a higher absorption coefficient
than the Cr$_2$TeAs and Cr$_2$TeSb monolayers in the visible region. The
results predict that Janus Cr$_2$TeX (X= P, As, Sb) monolayers with novel
properties have good potential for applications in future nanodevices.
