Local structural distortions and magnetism in lacunar spinel compounds

ORAL

Abstract

Lacunar spinels AB4Q8 (A=Al, Ga, Ge; B=V, Nb, Mo, Ta; Q=S, Se) display a variety of novel phenomena including skyrmion lattices and pressure-induced insulator-metal transitions and superconductivity. The high temperature structure features unique tetrahedral transition-metal clusters with S=1/2 moments on an FCC lattice. Low temperature distortions of these clusters are crucial to the properties of lacunar spinels. In skyrmion hosts GaV4S8 and GaV4Se8, a low temperature rhombohedral distortion allows for polar and magnetic order. In GaNb4Se8 and GaTa4Se8, antiferromagnetic interactions lead to geometric frustration and a quenched magnetization associated with a tetragonal distortion. We present results of local structural characterization on lacunar spinels in connection to their magnetic properties.

*This work was supported primarily by the NSF through the DMREF program DMR 1729489. The use of shared facilities from the Materials Research Science and Engineering Center (MRSEC) is gratefully acknowledged. The MRL Shared Experimental Facilities are supported by the MRSEC Program of the NSF under DMR 1720256; a member of the NSF-funded Materials Research Facilities Network (www.mrfn.org).

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Presenters

  • Julia Zuo

    • University of California, Santa Barbara

Authors

  • Julia Zuo

    • University of California, Santa Barbara

  • Emily C Schueller

    • University of California, Santa Barbara

  • Ram Seshadri

    • University of California, Santa Barbara
    • Materials Department and Materials Research Laboratory, University of California, Santa Barbara

  • Stephen D Wilson

    • University of California, Santa Barbara
    • Materials Department, University of California, Santa Barbara
    • California NanoSystems Institute, University of California, Santa Barbara