Realization of Opened and Closed Nodal Lines and Four- and Three-fold Degenerate Nodal Points in XPt (X = Sc, Y, La) Intermetallic Compound: A Computational Modeling Study.

Heju Xu

doi:10.3389/fchem.2020.609118

Abstract

Realizing rich topological elements in topological materials has attracted increasing attention in the fields of chemistry, physics, and materials science. Topological semimetals/metals are classified into three main types: nodal-point, nodal-line, and nodal-surface types with zero-, one-, and two-dimensional topological elements, respectively. This study reports that XPt (X = Sc, Y, La) intermetallic compounds are topological metals with opened and closed nodal lines, and triply degenerate nodal points (TNPs) when the spin–orbit coupling (SOC) is ignored. Based on the calculated phonon dispersions, one can find that ScPt and YPt are dynamically stable whereas LaPt is not. When SOC is added, the one-dimensional nodal line and zero-dimensional TNPs disappear. Interestingly, a new zero-dimensional topological element, that is, Dirac points with 4-fold degenerate isolated band crossings with linear band dispersion appear. The proposed materials can be considered a good platform to realize zero- and one-dimensional topological elements in a single compound and to study the relationship between zero- and one-dimensional topological elements.

Highlights

IntroductionWith the discovery of topological insulators (Cava et al, 2013; Kou et al, 2013; Zhao et al, 2013; Shen and Cha, 2014; Wang et al, 2014; Luo et al, 2015; Zhou et al, 2015; Liu et al, 2016; Chen et al, 2017a; Loïc and Izmaylov, 2017; Pan et al, 2017; Pielnhofer et al, 2017; Politano et al, 2017; Andrey et al, 2018; Hu et al, 2018, 2019; Gao et al, 2019; Mal et al, 2019; Qiao et al, 2019; Narimani et al, 2020), topologically non-trivial materials have attracted significant interest in the chemistry, physics, and materials science communities
A series of interesting topological signatures has been predicted in XPt (X = Sc, Y, La), and it is hoped that these proposed topological elements can be confirmed through experiments in the future

Summary

Introduction

With the discovery of topological insulators (Cava et al, 2013; Kou et al, 2013; Zhao et al, 2013; Shen and Cha, 2014; Wang et al, 2014; Luo et al, 2015; Zhou et al, 2015; Liu et al, 2016; Chen et al, 2017a; Loïc and Izmaylov, 2017; Pan et al, 2017; Pielnhofer et al, 2017; Politano et al, 2017; Andrey et al, 2018; Hu et al, 2018, 2019; Gao et al, 2019; Mal et al, 2019; Qiao et al, 2019; Narimani et al, 2020), topologically non-trivial materials have attracted significant interest in the chemistry, physics, and materials science communities. Topological semimetals/metals can be roughly classified into three main parts: nodal-point (Chen et al, 2015; Yuan et al, 2017; Zhang et al, 2017a,c, 2018c; Jing and Heine, 2018; Ma et al, 2018; Tsipas et al, 2018; Khoury et al, 2019), nodal-line (Chang et al, 2016; Liu et al, 2018b; Guo et al, 2019; Sankar et al, 2019; Tang et al, 2019; Xu et al, 2019; Zhang et al, 2019; Jin et al, 2020a; Kirby et al, 2020; Zhou et al, 2020), and nodal-surface (Türker and Sergej, 2018; Wu et al, 2018; Zhang et al, 2018b,d; Fu et al, 2019; Yang et al, 2019b, 2020; Chen et al, 2020; Wang et al, 2020e; Xiao et al, 2020) semimetals/metals enjoying zero-, one-, and two-dimensional topological elements, respectively. In 2019, Yang et al (2019a) experimentally demonstrated TNP as well as double Fermi arc surface states in a three-dimensional phononic crystal

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Results

Conclusion