Observation of Dirac-like band dispersion in LaAgSb$_2$

TL;DR

This study combines ARPES experiments and first-principles calculations to reveal a Dirac-like band structure in LaAgSb$_2$, linking it to charge-density-wave phenomena and exotic electronic behaviors.

Contribution

It provides the first direct observation of Dirac-cone-like dispersion in LaAgSb$_2$ and connects it to charge-density-wave ordering.

Findings

Dirac-cone-like structure observed near Fermi level

Nested Fermi surface segments from the Dirac cone

Connection between Dirac dispersion and charge-density-wave order

Abstract

We present a combined angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations study of the electronic structure of LaAgSb$_2$ in the entire first Brillouin zone. We observe a Dirac-cone-like structure in the vicinity of the Fermi level formed by the crossing of two linear energy bands, as well as the nested segments of Fermi surface pocket emerging from the cone. Our ARPES results show the close relationship of the Dirac cone to the charge-density-wave ordering, providing consistent explanations for exotic behaviors in this material.