Spin gapless semiconductors

TL;DR

Spin gapless semiconductors are a novel class of materials with fully spin-polarized electrons and holes, offering promising applications in high-speed, low-energy spintronic devices due to their unique band structures and potential for dissipationless edge states.

Contribution

This paper provides a comprehensive review of both Dirac and parabolic types of spin gapless semiconductors across various material systems, highlighting their properties and potential applications.

Findings

Dirac type SGSs exhibit fully spin-polarized Dirac cones.

Parabolic SGSs have been predicted and some experimentally demonstrated.

SGSs have significant potential in next-generation spintronic devices.

Abstract

Spin gapless semiconductors (SGSs) are a new class of zero gap materials which have a fully spin polarised electrons and holes. They bridge zero gap materials and half-metals. The band structures of the SGSs can have two types of energy dispersions: Dirac linear dispersion and parabolic dispersion. The Dirac type SGSs exhibit fully spin polarized Dirac cones, and offer a platform for massless and fully spin polarized spintronics as well as dissipationless edge state via quantum anomalous Hall effect. Due to its fascinating spin and charge states, they hold great potential application in spintronics. There have been tremendous efforts worldwide on searching for suitable candidates of SGSs. In particularly, there is an increasing interest in searching for Dirac type SGSs. In the past decade, a large number of Dirac or parabolic type SGSs have been predicted by density functional theory and some of parabolic SGSs have been experimentally demonstrated. The SGSs hold great potential for high speed and low-energy consumption spintronics, electronics and optoelectronics. Here, we review both Dirac and parabolic types of SGSs in different materials systems and outline the concepts of SGSs, novel spin and charge states, and potential applications of SGSs in next generation spintronic devices.