Dimensional crossover in a van der Waals ferromagnet detected by spin correlation driven distortions

ORAL

Abstract

Magneto-elasticity – the structural deformation of a crystal in response to a change in its magnetic energy – is commonly detected across magnetic long-range ordering (LRO) transitions and yields insight into magnetic ground state energetics. In principle, distortions are also induced by magnetic short-range ordering (SRO), which provide complementary information about short-range correlations and energetics that are essential for understanding how LRO is established. However these distortions are difficult to resolve because the associated atomic displacements are exceedingly small and do not break symmetry. Here we demonstrate high-multipole nonlinear optical polarimetry as a sensitive and mode selective probe of SRO induced distortions using CrSiTe3 as a testbed. This compound is composed of van der Waals bonded sheets of ferromagnetically interacting Heisenberg spins that, in isolation, would be impeded from LRO by the Mermin-Wagner theorem. Our results show that CrSiTe3 evades this law via a two-step crossover from two- to three-dimensional magnetic SRO above its Curie temperature (Tc=31K), manifested through two previously undetected totally symmetric distortions at T2D~110K and T3D~60K, respectively. Such data open new avenues for mechanical control of magnetism.

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Presenters

  • Alon Ron

    Caltech, Department of Physics, California Institute of Technology

Authors

  • Alon Ron

    Caltech, Department of Physics, California Institute of Technology

  • Eli Zoghlin

    University of California, Santa Barbara, Materials Department, University of California, Santa Barbara, Materials, University of California, Santa Barbara

  • Leon Balents

    Physics, University of California Santa Barbara, Kavli Institute for Theoretical Physics, University of California, Santa Barbara, University of California, Santa Barbara, Kavli Institute for Theoretical Physics, UCSB

  • Stephen Wilson

    University of California, Santa Barbara, Materials Department, University of California, Santa Barbara, Materials, University of California Santa Barbara, Materials, University of California, Santa Barbara, UC Santa Barbara

  • David Hsieh

    California Institute of Technology, Institute for Quantum Information and Matter, California Institute of Technology, Caltech, Caltech, Physics, Math & Astronomy, Physics, California Institute of Technology, Department of Physics, California Institute of Technology