Possible emergence of a skyrmion phase in ferroelectric GaMo${}_4$S${}_8$

Abstract

Polar lacunar spinels, such as GaV${}_4$S${}_8$ and GaV${}_4$Se${}_8$, were proposed to host skyrmion phases under magnetic field. In this work, we put forward, as a candidate for Néel-type skyrmion lattice, the isostructural GaMo${}_4$S${}_8$, here systematically studied via both first-principles calculations and Monte Carlo simulations of model Hamiltonian. Electric polarization, driven by Jahn-Teller distortion, is predicted to arise in GaMo${}_4$S${}_8$, showing a comparable size but an opposite sign with respect to that evaluated in V-based counterparts and explained in terms of different electron counting arguments and resulting distortions. Interestingly, a larger spin-orbit coupling of 4d orbitals with respect to 3d orbitals in vanadium-spinels leads to stronger Dzyaloshinskii-Moriya interactions, which are beneficial to stabilize a cycloidal spin texture, as well as smaller-sized skyrmions (radius<10 nm). Furthermore, the possibly large exchange anisotropy of GaMo4S8 may lead to a ferroelectric-ferromagnetic ground state, as an alternative to the ferroelectric-skyrmionic one, calling for further experimental verification.

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References in corpus (8)

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• Architecture of nanoscale ferroelectric domains in GaMo4S8

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• Antiferromagnetic Skyrmions and Skyrmion Density Wave in Rashba Hund's Insulator
• Skyrmionic order and magnetically induced polarization change in lacunar spinel compounds GaV${}_4$S${}_8$ and GaMo${}_4$S${}_8$: comparative theoretical study
• Magnetoentropic mapping and computational modeling of cycloids and skyrmions in the lacunar spinels GaV${}_4$S${}_8$ and GaV${}_4$Se${}_8$
• Magnetoelectric imprint of skyrmions in van der Waals bilayers
• Spin dynamics in the skyrmion-host lacunar spinel GaV4S8
• Comparison of skyrmion phases between poly and single-crystal MnSi by composite magnetoelectric method
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