of a bulk Weyl nodes. Instead we see signatures of a gapped Dirac dispersion, common in other members of AMnBi$_2$ family or compounds with similar 2D network of Bi atoms. We speculate that the evidence for a WSM seen in ARPES arises through a surface magnetic phase. Such an assumption reconciles all known experimental data.'
author:
- Dipanjan Chaudhuri
- Bing Cheng
- Alexander Yaresko
- 'Quinn D. Gibson'
- 'R. J. Cava'
- 'N. P. Armitage'
title: 'An optical investigation of the strong spin-orbital coupled magnetic semimetal YbMnBi$_2$'
---

Introduction
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Correlated electron systems with strong SOC have been the subject of intensive research in recent years. The interplay of electronic correlations and SOC can result in emergent topological phases and has opened up a completely new direction in condensed matter physics. This interplay can be very different depending on the specifics of the electronic correlation. In weakly to moderately interacting electron systems, SOC can lead to non-trivial band topology as observed in conventional topological insulators [@moore2009topological], Dirac and Weyl semi-metals [@Balents; @turner2013beyond; @armitage2017weyl], axion insulators [@wan2012computational] and topological superconductors [@qi2011topological]. More recently, the effects of SOC on strongly correlated systems are being explored with the realization of new 