  The synthesis of antimonene, which is a promising group-V 2D material for
both fundamental studies and technological applications, remains highly
challenging. Thus far, it has been synthesized only by exfoliation or growth on
a few substrates. In this study, we show that thin layers of antimonene can be
grown on Ag (111) by molecular beam epitaxy. High-resolution scanning tunneling
microscopy combined with theoretical calculations revealed that the
submonolayer Sb deposited on a Ag (111) surface forms a layer of AgSb2 surface
alloy upon annealing. Further deposition of Sb on the AgSb2 surface alloy
causes an epitaxial layer of Sb to form, which is identified as antimonene with
a buckled honeycomb structure. More interestingly, the lattice constant of the
epitaxial antimonene (5 {\AA}) is much larger than that of freestanding
antimonene, indicating a high tensile strain of more than 20%. This kind of
large strain is expected to make the antimonene a highly promising candidate
for room-temperature quantum spin Hall material.
