Spin selectivity in elemental tellurium and other chiral materials

Abstract

The phenomenon of chirality-induced spin selectivity (CISS), where chiral organic molecules enable the selective transmission of electrons spin-polarized along the direction of electric current, has been studied for nearly two decades. Despite its technological relevance, CISS is not fully understood. Recent studies have expanded the concept of spin selectivity to chiral inorganic crystals, offering promise for magnet-free spintronics and other applications. This Perspective reviews recent developments on spin selectivity in non-magnetic solid-state materials, whereby chirality-dependent charge-to-spin conversion is responsible for transforming electric currents into spin signals, and spin transport within devices. Notably, chiral systems often outperform non-chiral ones in terms of conversion efficiency and facilitate long-range spin transport, which makes them relevant for both fundamental and applied physics. After examining the archetypal example of the chiral crystal, elemental tellurium, and the studies of spin selectivity in Weyl semimetals, we discuss its origin in terms of the unconventional (collinear) Rashba–Edelstein effect. We also explore key factors affecting the conversion efficiency and robustness of spin transport, focusing on persistent spin textures and their influence on spin lifetime. In addition, we discuss the potential impact of band velocities and the role of orbital contributions, as well as the differences associated with reduced dimensionality, providing a roadmap for guiding future theoretical, experimental, and applied studies.