Unexpected changes in the band structure within AFM1 state of CeBi

TL;DR

This study combines ARPES measurements and DFT calculations to reveal a new AFM transition and complex electronic structure changes in CeBi, revising its phase diagram to include three AFM states.

Contribution

It uncovers a previously unknown AFM transition and details the evolution of surface and Dirac states across multiple AFM phases in CeBi.

Findings

Discovery of a new AFM transition in CeBi.

Development of an additional Dirac state in the (+-+-) phase.

Transformation of surface-state pairs in the (++--) phase.

Abstract

We perform angle-resolved photoemission spectroscopy (ARPES) measurements in conjunction with density functional theory (DFT) calculations to investigate the evolution of the electronic structure of CeBi upon a series of antiferromagnetic (AFM) transitions. We find evidence for a new AFM transition in addition to two previously known from transport studies. We demonstrate the development of an additional Dirac state in the (+-+-) ordered phase and a transformation of unconventional surface-state pairs in the (++--) ordered phase. This revises the phase diagram of this intriguing material, where there are now three distinct AFM states below TN in zero magnetic field instead of two as it was previously thought.