Topological materials discovery by large-order symmetry indicators.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30873432.
- Also identified by DOI 10.1126/sciadv.aau8725 and PMC identifier 6408154.
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Abstract
Crystalline symmetries play an important role in the classification of band structures, and their richness leads to various topological crystalline phases. On the basis of our recently developed method for the efficient discovery of topological materials using symmetry indicators, we explore topological materials in five space groups ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi></mrow> </mrow> </math> s), which are diagnosed by large-order symmetry indicators (ℤ<sub>8</sub> and ℤ<sub>12</sub>) and support the coexistence of several kinds of gapless boundary states in a single compound. We predict many candidate materials; some representatives include Pt<sub>3</sub>Ge ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi> <mspace></mspace> <mn>140</mn></mrow> </mrow> </math> ), graphite ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi> <mspace></mspace> <mn>194</mn></mrow> </mrow> </math> ), <i>X</i>Pt<sub>3</sub> ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi> <mspace></mspace> <mn>221</mn></mrow> </mrow> </math> , <i>X</i> = Sn, Pb), Au<sub>4</sub>Ti ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi> <mspace></mspace> <mn>87</mn></mrow> </mrow> </math> ), and Ti<sub>2</sub>Sn ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi> <mspace></mspace> <mn>194</mn></mrow> </mrow> </math> ). As by-products, we also find that Ag<i>X</i>F<sub>3</sub> ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi> <mspace></mspace> <mn>140</mn></mrow> </mrow> </math> , <i>X</i> = Rb, Cs) and AgAs<i>X</i> ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mi>S</mi> <mi>G</mi> <mspace></mspace> <mn>194</mn></mrow> </mrow> </math> , <i>X</i> = Sr, Ba) are good Dirac semimetals with clean Fermi surfaces. The proposed materials provide a good platform for studying the novel properties emerging from the interplay between different types of boundary states.