Topological Nodal Line Electrides: Realization of Ideal Nodal Line State Nearly Immune from Spin-Orbit Coupling

TL;DR

This paper introduces topological nodal line electrides (TNLEs), a new class of materials that exhibit nearly SOC-immune nodal lines and electrides, with potential for studying intrinsic topological properties.

Contribution

The work proposes TNLEs that combine nodal line semimetal properties with electride characteristics, especially in A2B compounds, showing minimal SOC-induced gaps even with heavy elements.

Findings

TNLEs exhibit extremely small SOC-induced gaps.

A2B compounds are realistic TNLE candidates.

TNLEs provide platforms for studying intrinsic topological properties.

Abstract

Nodal line semimetals (NLSs) have attracted broad interest in current research. In most of existing NLSs, the intrinsic properties of nodal lines are greatly destroyed because nodal lines usually suffer sizable gaps induced by non-negligible spin-orbit coupling (SOC). In this work,we propose the topological nodal line electrides (TNLEs), which achieve electronic structures of nodal lines and electrides simultaneously, provide new insight on designing excellent NLSs nearly immune from SOC. Since the states near the Fermi level are most contributed by nonnucleus-bounded interstitial electrons, nodal lines in TNLEs manifest extremely small SOCinduced gap even possessing heavy elements. Especially, we propose the family of A2B (A = Ca, Sr, Ba; B= As, Sb, Bi) materials are realistic TNLEs with negligible SOC-induced gaps, which can play as excellent platforms to study the intrinsic properties of TNLEs