Observation of Dirac-Like Semi-Metallic Phase in NdSb

TL;DR

This study uses ARPES to identify Dirac-like semi-metallic states in NdSb, revealing potential new topological phases and suggesting further exploration in rare earth monopnictides.

Contribution

First experimental observation of Dirac-like states in NdSb, indicating a possible new correlated topological semi-metallic phase.

Findings

Dirac-like linearly dispersive states observed at the X point

Fermi surface pockets identified at Γ and X points

First principles calculations support experimental band observations

Abstract

The search of new topological phases of matter is one of the new directions in condensed matter physics. Recent experimental realizations of Dirac semimetal phases pave the way to look for other exotic phases of matter in real materials. Here we present a systematic angle-resolved photoemission spectroscopy (ARPES) study of NdSb, a potential candidate for hosting a Dirac semi-metal phase. Our studies reveal two hole-like Fermi surface pockets present at the zone center ($\Gamma$) point as well as two elliptical electron-pockets present in the zone corner (X) point of the Brillouin zone (BZ). Interestingly, Dirac-like linearly dispersive states are observed about the zone corner (X) point in NdSb. Our first principles calculations agree with the experimentally observed bands at the $\Gamma$ point. Moreover, the Dirac-like state observed in NdSb may be a novel correlated state, not yet predicted in calculations. Our study opens a new direction to look for Dirac semi-metal states in other members of the rare earth monopnictide family.