Concept of multichannel spin-resolving electron analyzer based on Mott scattering

TL;DR

This paper introduces a multichannel electron spin detector based on Mott scattering and optical imaging, significantly increasing efficiency and enabling advanced spin-resolved spectroscopies for various materials and applications.

Contribution

It presents a novel multichannel spin detector concept using optical imaging and Mott scattering with high efficiency and broad applicability.

Findings

Efficiency gain of over 10,000 times compared to single-channel detectors

Capability to image spin asymmetry in parallel across multiple channels

Potential applications in studying topological insulators and heterostructures

Abstract

Concept of a multichannel electron spin detector based on optical imaging principles and Mott scattering (iMott) is presented. A multichannel electron image produced by standard angle-resolving (photo) electron analyzer or microscope is re-imaged by an electrostatic lens at an accelerating voltage of 40 keV onto the Au target. Quasi-elastic electrons bearing spin asymmetry of the Mott scattering are imaged by magnetic lenses onto position-sensitive electron CCDs whose differential signals yield the multichannel spin asymmetry image. Fundamental advantages of this concept include acceptance of inherently divergent electron sources from the electron analyzer or microscope focal plane as well as small aberrations achieved by virtue of high accelerating voltages, as demonstrated by extensive ray-tracing analysis. The efficiency gain compared to the single-channel Mott detector can be a factor of more than 1e4 which opens new prospects of spin-resolved spectroscopies in application not only to standard bulk and surface systems (Rashba effect, topological insulators, etc.) but also to buried heterostructures. The simultaneous spin detection and fast CCD readout enable efficient use of the iMott detectors at X-ray FEL facilities.