Experimental determination of the topological phase diagram in Cerium monopnictides

TL;DR

This study uses soft X-ray ARPES to map the topological phase diagram of Ce monopnictides, revealing a transition from trivial to nontrivial topology driven by spin-orbit coupling and band inversion.

Contribution

It provides the first experimental topological phase diagram of CeX monopnictides, demonstrating the topological phase transition induced by SOC and band inversion.

Findings

Identified the topological phase transition from CeP to CeBi.

Mapped the bulk electronic structures across different CeX compounds.

Elucidated the role of spin-orbit coupling in driving the topological transition.

Abstract

We use bulk-sensitive soft X-ray angle-resolved photoemission spectroscopy and investigate bulk electronic structures of Ce monopnictides (CeX; X=P, As, Sb and Bi). By exploiting a paradigmatic study of the band structures as a function of their spin-orbit coupling (SOC), we draw the topological phase diagram of CeX and unambiguously reveal the topological phase transition from a trivial to a nontrivial regime in going from CeP to CeBi induced by the band inversion. The underlying mechanism of the topological phase transition is elucidated in terms of SOC in concert with their semimetallic band structures. Our comprehensive observations provide a new insight into the band topology hidden in the bulk of solid states.