High-resolution Spin- and Angle-resolved photoelectron spectroscopy with Laser Light at LASOR
Spin- and angle-resolved photoelectron spectroscopy (SARPES) is a powerful technique to investigate the spin-dependent electronic states in solids. From FY 2014, We started a project constructing new SARPES apparatus using laser light. Our new system is designed to provide high-energy and -angular resolution and high efficiency of spin detection for SARPES.The apparatus is equipped a high-energy resolution photoelectron analyzer (VG Scienta, D80 analyzer) with deflectors (VG Scienta, DA30L) and two high efficient spin detectors associating very low energy electron diffraction (VLEED), which allows us to analyze the three-dimensional spin polarization of electrons.
The electrons are excited with 6.994 eV photons, yielded by 6th harmonic of a Nd:YVO4 quasi-continuous wave laser with repetition rate of 80 MHz. A He discharge lamp (VG Scienta, VUV5000) is also available as a photon source. Samples are cooled by the liquid He cryostat below 9 K. The experiment station also consists of an MBE chamber and a carousel chamber connected to a load-lock chamber. The surface evaluating and preparing instruments, such as evaporators, LEED, RHEED, Sputter-gun, quartz microbalance can be installed. The new SARPES system is utilized to obtain precise information on spin-dependent electronic structures near the Fermi level in solids. Joint research at this station has been started from FY 2015.