Signatures of Z3 Vestigial Potts-nematic order in van der Waals antiferromagnets

ORAL

Abstract

Layered van der Waals magnets have attracted much recent attention as a promising and versatile platform for exploring intrinsic two-dimensional magnetism. Within this broader class, the transition metal phosphorous trichalcogenides MPX3 stand out as particularly interesting, as they provide a realization of honeycomb lattice magnetism and are known to display a variety of magnetic ordering phenomena. Here, we report the observation of key signatures of vestigial Potts-nematic order in rhombohedral FePSe3. By performing linear dichroism imaging measurements—an ideal probe of rotational symmetry breaking—we find that the C3 symmetry is already broken above the Néel temperature. We show that these observations are explained by a general Ginzburg-Landau model of vestigial nematic order driven by magnetic fluctuations and coupled to residual strain. An analysis of the domain structure as temperature is lowered and a comparison with zigzag-ordered monoclinic FePS3 reveals a broader applicability of the Ginzburg-Landau model in the presence of external strain, and firmly establishes the MPX3 magnets as a new experimental venue for studying the interplay between Potts-nematicity, magnetism and superconductivity.

* The project design, data collection and analysis are supported by L.W.'s startup package at the University of Pennsylvania. The development of the scanning imaging microscope was sponsored by the Army Research Office and was accomplished under Grant Number W911NF20-2-0166 and W911NF-21-1-0131, and the University Research Foundation. The sample exfoliation setup is based upon work supported by the Air Force Office of Scientific Research under award number FA9550-22-1-0449. Z.N. also acknowledges support from Vagelos Institute of Energy Science and Technology graduate Fellowship and Dissertation Completion Fellowship at the University of Pennsylvania. D.G.M acknowledges support from the Gordon and Betty Moore Foundation's EPiQS Initiative, Grant GBMF9069. W.J.M. and R.M.F. (theoretical model and numerical calculations) were supported by the U. S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under Award No. DESC0020045. W.J.M and R.M.F. thank the Minnesota Supercomputing Institute (MSI) at the University of Minnesota, where the numerical computations were performed. J.W.F.V was supported by the National Science Foundation Award No. DMR-2144352

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Publication: arXiv:2308.07249

Presenters

  • Qi Tian

    UPenn

Authors

  • Qi Tian

    UPenn