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arXiv · 2405.16432

Revealing the hidden Dirac gap in a topological antiferromagnet using Floquet-Bloch manipulation

Nina Bielinski·Rajas Chari·Julian May-Mann·Soyeun Kim·Jack Zwettler·Yujun Deng·Anuva Aishwarya·Subhajit Roychowdhury·Chandra Shekhar·Makoto Hashimoto·Donghui Lu·Jiaqiang Yan·Claudia Felser·Vidya Madhavan·Zhi-Xun Shen·Taylor L. Hughes·Fahad Mahmood
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Abstract

Manipulating solids using the time-periodic drive of a laser pulse is a promising route to generate new phases of matter. Whether such `Floquet-Bloch' manipulation can be achieved in topological magnetic systems with disorder has so far been unclear. In this work, we realize Floquet-Bloch manipulation of the Dirac surface-state mass of the topological antiferromagnet (AFM) MnBi$_2$Te$_4$. Using time- and angle-resolved photoemission spectroscopy (tr-ARPES), we show that opposite helicities of mid-infrared circularly polarized light result in substantially different Dirac mass gaps in the AFM phase, despite the equilibrium Dirac cone being massless. We explain our findings in terms of a Dirac fermion with a random mass. Our results underscore Floquet-Bloch manipulation as a powerful tool for controlling topology even in the presence of disorder, and for uncovering properties of materials that may elude conventional probes.

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Nina Bielinski, Rajas Chari, Julian May-Mann, Soyeun Kim, Jack Zwettler, Yujun Deng, Anuva Aishwarya, Subhajit Roychowdhury, Chandra Shekhar, Makoto Hashimoto, Donghui Lu, Jiaqiang Yan, Claudia Felser, Vidya Madhavan, Zhi-Xun Shen, Taylor L. Hughes, Fahad Mahmood. 2024-05-26. Revealing the hidden Dirac gap in a topological antiferromagnet using Floquet-Bloch manipulation. https://arxiv.org/abs/2405.16432

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