A high-efficiency spin-resolved phototemission spectrometer combining time-of-flight spectroscopy with exchange-scattering polarimetry

TL;DR

This paper introduces a highly efficient, high-resolution spin-resolved photoemission spectrometer that combines time-of-flight energy analysis with exchange-scattering polarimetry, significantly improving measurement efficiency and resolution for spin-ARPES applications.

Contribution

The paper presents a novel spectrometer design integrating TOF analysis with exchange-scattering polarimetry, achieving unprecedented efficiency and resolution in spin-resolved electron spectroscopy.

Findings

Achieved up to 100 times higher efficiency than traditional Mott polarimeters.

Demonstrated high energy resolution in spin-ARPES measurements.

Suitable for time-resolved spin-ARPES experiments.

Abstract

We describe a spin-resolved electron spectrometer capable of uniquely efficient and high energy resolution measurements. Spin analysis is obtained through polarimetry based on low-energy exchange scattering from a ferromagnetic thin-film target. This approach can achieve a similar analyzing power (Sherman function) as state-of-the-art Mott scattering polarimeters, but with as much as 100 times improved efficiency due to increased reflectivity. Performance is further enhanced by integrating the polarimeter into a time-of-flight (TOF) based energy analysis scheme with a precise and flexible electrostatic lens system. The parallel acquisition of a range of electron kinetic energies afforded by the TOF approach results in an order of magnitude (or more) increase in efficiency compared to hemispherical analyzers. The lens system additionally features a 90{\deg} bandpass filter, which by removing unwanted parts of the photoelectron distribution allows the TOF technique to be performed at low electron drift energy and high energy resolution within a wide range of experimental parameters. The spectrometer is ideally suited for high-resolution spin- and angle-resolved photoemission spectroscopy (spin-ARPES), and initial results are shown. The TOF approach makes the spectrometer especially ideal for time-resolved spin-ARPES experiments.