Performance of the spin- and angle- resolved photoemission spectrometer with highly efficient VLEED spin detector

Because of the growing scientific interests in the spin-related exotic materials such as topological insulators, spin- and angle- resolved photoemission with much improved efficiency is strongly desired. In this report, we present the current status of a new SARPES with significantly improved energy- ($\Delta E)$ and angular resolutions ($\Delta \theta )$, which is under construction at beam line BL-9B in Hiroshima Synchrotron Radiation Center. The system consists of high performance hemispherical analyzer (VG-Scienta R-4000) and highly efficient spin detector based on very low energy electron diffraction of Fe(001)p(1x1)-O, which has 100 times higher efficiency than conventional Mott spin detector. Owing to the high efficiency of the detector, the highest $\Delta E$ and $\Delta \theta $ have been improved to be 7.5 meV and 0.37$^{o}$. Moreover, high-resolution ARPES measurement ($\Delta E \quad \sim $ 2meV, $\Delta \theta \quad \sim $ 0.2$^{o})$ and Fermi surface mapping in the sample temperature range from 8K to room temperature can be efficiently performed by hemispherical analyzer equipped with multi-channel detector and motorized 5 axis goniometer. These features of the SARPES enable us to observe detailed spin-dependent band structures of topological insulators very precisely and efficiently.