Multiple Triple-Point Fermions in Heusler Compounds

TL;DR

This paper predicts multiple topological triple point fermions in Heusler compounds using density functional theory, revealing exotic quasiparticles with potential for quantum transport, and simulates their surface states and Fermi arcs.

Contribution

It introduces a new class of topological semimetals with multiple triple point fermions in Heusler compounds, including detailed surface state analysis and effects of spin-orbit coupling.

Findings

Multiple triple point fermions found along four $C_{3}$ axes.

Surface states and Fermi arcs simulated for these compounds.

Spin-orbit coupling splits triple points into Dirac points.

Abstract

Using the density functional theoretical calculations, we report a new set of topological semimetals X$_{2}$YZ (X = \{Cu, Rh, Pd, Ag, Au, Hg\}, Y = \{Li, Na, Sc, Zn, Y, Zr, Hf, La, Pr, Pm, Sm, Tb, Dy, Ho, Tm\} and Z =\{Mg, Al, Zn, Ga, Y, Ag, Cd, In, Sn, Ta, Sm\}), which show the existence of multiple topological triple point fermions along four independent $C_{3}$ axes. These fermionic quasiparticles have no analogues elementary particle in the standard model. The angle-resolved photoemission spectroscopy is simulated to obtain the exotic topological surface states and the characteristic Fermi arcs. The inclusion of spin-orbit coupling splits the triple-point into two Dirac points. The triple-point fermions are exhibited on the easily cleavable (111) surface and are well separated from the surface $\bar{\Gamma}$ point, allowing them to be resolved in the surface spectroscopic techniques. This intermediate linearly dispersive degeneracy between Weyl and Dirac points may offer prospective candidates for quantum transport applications.