Computational discovery of spin-polarized semimetals in spinel materials

TL;DR

This study uses first-principles calculations to identify spin-polarized semimetal candidates in spinel materials, revealing their unique nodal chain structures and potential for spintronic applications.

Contribution

It introduces two new spinel materials, VZn2O4 and VCd2S4, as spin-polarized semimetals with protected nodal chain features, expanding the material options for spintronics.

Findings

VZn2O4 and VCd2S4 are ferromagnetic spin-polarized semimetals.

Their electronic bands form protected nodal rings and chains.

The nodal chain structure is described by a four-band tight-binding model.

Abstract

The materials with spin-polarized electronic states have attracted a huge amount of interest due to their potential applications in spintronics. Based on first-principles calculations, we study the electronic characteristics of a series of AB2X4 chalcogeniden spinel structures and propose two promising candidates, VZn2O4 and VCd2S4, are spin-polarized semimetal materials. Both of them have ferromagnetic ground states. Their bands near the Fermi level are completely spin-polarized and form two types of nodal rings in the spin-up channel, and the large gaps in the spin-down channel prevent the spin-flip. Further symmetry analysis reveals that the nodal rings are protected by the glide mirror or mirror symmetries. Significantly, these nodal rings connect with each other and form a nodal chain structure, which can be well described by a simple four-band tight-binding (TB) model. The two ternary chalcogeniden spinel materials with a fully spin polarized nodal chain can serve as a prominent platform in the future applications of spintronic.