Integrated High Efficiency Spin-Polarimeters – POLARSPIN

The development of sources and detectors of spin-polarized free electron beams has given access to various spin-dependent processes that occur in physics. With the use of spin-polarized electron sources, fundamental and technological progress has been made in condensed matter and surface/material science. Nevertheless, the practical manipulation of the spin polarization of a free electron beam is not as usual as it is for photons. The famous Stern-Gerlach technique, which allows to select fully polarized free atom beams, fails for electrons because of their charge. Thus, different methods have been investigated, and are still being investigated, for producing and analyzing spin-polarized electron beams.

The measurement of the spin polarization of a free electron beam still relies today on heavy-handling experiments, which require severe operating conditions (high voltages, ultra-high vacuum conditions, cumbersome installation, surface preparation requirements, etc). The development of more convenient electron spin detectors would then be of great interest, not only for spin-resolved electron spectroscopy and microscopy techniques, but also to spread worldwide the capability to measure spin-dependent phenomena in already existing experiments, for example available in laboratories or large user facilities, without the need of being an expert in spin polarimetry.

The POLARSPIN project is designed to bring from a technology concept to a laboratory prototype a new breed of electron spin polarimeter for cutting edge scientific instrumentation. The specifications (spin discriminating power and figure of merit) of the proposed polarimeter are forecasted to be competitive with current technology. More importantly, their ease of use and controlled cost should bring a new impulse in democratizing the implementation of spin-resolved (possibly angular resolved) photoemission spectroscopy techniques in laboratories and synchrotron radiation facilities. We also envision that the POLARSPIN polarimeter could be used to upgrade existing scanning electron microscopes (SEM) to provide magnetic contrast, similar to what is done in the very few worldwide SEM with polarization analysis (SEMPA), which are currently equipped with Mott or SPLEED detectors. Spreading technological solutions allowing the detection of the electron spin polarization in a routinely fashion, and not only via confidential, complex techniques, would certainly open new avenues in scientific instrumentation that could lead to new discoveries in physics.

The physics at the origin of the POLARSPIN project being mainly understood, the challenge here is to fabricate a series of performant prototypes that could be tested and benchmarked prior to their transfer to the industrial sector. The POLARSPIN project, through its structure, will naturally favor the development of a strong collaboration between two academic partners and the CRYOSCAN start-up. All partners will benefit from the project achievements by increasing their fundamental knowledge on spin-polarized hot electrons transport in solid state devices. Moreover, CRYOSCAN will extend its field of activities by proposing an exclusive and innovating new product for the national and international markets. A successful POLARSPIN project will indeed provide a reliable spin detector prototype with a demonstrated easy implementation and efficiency in spin-resolved photoemission spectroscopy measurements. As we aim to disrupt the market of electron spin detection technologies, the POLARSPIN project will strongly reinforce the development of CRYOSCAN. Thus, the exclusive technological knowledge acquired by the POLARSPIN consortium will establish a sustainable competitiveness and develop the attractiveness of both the academics and industrial partners.