Prediction of Ideal Triple Degenerate Points in HfIrAs and HfIrBi

Abstract

In this study, two ideal triple degenerate point (TDP) semimetals were predicted, namely, HfIrAs and HfIrBi, that exhibit clean TDPs around the fermi level. At the atomic level, the origin of the TDP was analyzed, and when combined with the low-energy effective 4-band model, it was found that the bulk inversion asymmetry directly determines the formation of the TDP for cubic crystals. The projected surface states and corresponding patterns of the fermi arcs with and without tensile strain were investigated for two different crystal face orientations [(111) and (110)], both of which could be detected using photoemission spectroscopy. In addition, the disappearance of the spin texture, which was studied in strained HgTe bulk states, was also observed in the surface states. The results of this study indicate that the two materials are unique platforms on which emergent phenomena, such as the interplay between the TDP of semimetals and superconductivity, can be explored.