  Atomically thin PtSe2 films have attracted extensive research interests for
potential applications in high-speed electronics, spintronics and
photodetectors. Obtaining high quality, single crystalline thin films with
large size is critical. Here we report the first successful layer-by-layer
growth of high quality PtSe2 films by molecular beam epitaxy. Atomically thin
films from 1 ML to 22 ML have been grown and characterized by low-energy
electron diffraction, Raman spectroscopy and X-ray photoemission spectroscopy.
Moreover, a systematic thickness dependent study of the electronic structure is
revealed by angle-resolved photoemission spectroscopy (ARPES), and helical spin
texture is revealed by spin-ARPES. Our work provides new opportunities for
growing large size single crystalline films for investigating the physical
properties and potential applications of PtSe2.
