Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 11: Focus: Progress in Spin-Polarized Electron Spectroscopies

MA 11.4: Hauptvortrag

Montag, 16. März 2015, 17:00–17:30, EB 301

High-efficiency spin-resolved ARPES with a TOF-based exchange polarimeter — •Chris Jozwiak — Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, California, U.S.A.

A strong fundamental interest in the spin-degree of freedom in electronic systems has driven decades of persistence and creativity in developing a range of methods for spin-resolved photoemission spectroscopy. The demanding but powerful technique of Spin- and Angle-Resolved Photoemission Spectroscopy (Spin-ARPES) has steadily expanded in the last decade due to an increasing demand for probing momentum dependent electronic spin in a wide variety of materials. Strongly spin-orbit coupled materials, including Topological Insulators (TIs), have particularly stimulated advancement of the technique due to characteristic momentum-dependent spin-textures. I will present an overview of the "spin-TOF analyzer", an instrument developed at the ALS for high-resolution and high-efficiency spin-ARPES [1]. The analyzer combines the efficiency of low energy exchange scattering spin detection (e.g. [2]) with the parallel energy resolution of time-of-flight (TOF) detection (e.g. [3]). I will describe details of this unique combination and present examples of its use with both synchrotron light and lab-based laser systems, focusing on the observations of surprising spin-polarization effects in the photoemission from TIs [4]. --- [1] C. Jozwiak et al., Rev. Sci. Instrum. 82, 053904 (2010). [2] Hillebrecht et al., Rev. Sci. Instrum. 73, 1229 (2002). [3] N. Müller et al., J. El. Spectr. Rel. Phenom. 72, 187 (1995). [4] C. Jozwiak et al., Nature Phys. 9, 293 (2013).