Topology of triple-point metals

We discuss and illustrate the appearance of topological fermions and bosons in triple-point metals where a band crossing of three electronic bands occurs close to the Fermi level.Topological bosons appear in the phonon spectrum of certain triple-point metals, depending on the mass of atoms that form the binary triple-point metal.We first provide a classification of possible triple-point electronic topological phases possible in crystalline compounds and discuss the consequences of these topological phases, seen in Fermi arcs, topological Lifshitz transitions, and transport anomalies.Then we show how the topological phase of phonon modes can be extracted and proven for relevant compounds.Finally,we show how the interplay of electronic and phononic topologies in triple-point metals puts these metallic materials into the list of the most efficient metallic thermoelectrics known to date.

看到了Ⅱ型狄拉克费米子

粒子物理的标准模型描述了所有已知的基本粒子,如电子和夸克。这些粒子在凝聚态物质中,通常具有类似物,其表现形式为集体态或准粒子。一个例子是在石墨烯中的电子态,它的行为像一个无质量的狄拉克费米子——粒子自旋为1/2,反粒子不是它自己。与标准模型相比,凝聚态物理可以提供为数更多的＂基本粒子＂。这是由于这样的事实：不同于基本粒子,固体中的准粒子不受所谓的洛伦兹不变性约束。