Geometrically frustrated magnets provide abundant opportunities for discovering complex spin textures, which sometimes yield unconventional electromagnetic responses in correlated electron systems. It is theoretically predicted that magnetic frustration may also promote a topologically nontrivial spin state, i.e., magnetic skyrmions, which are nanometric spin vortices. Empirically, however, skyrmions are essentially concomitant with noncentrosymmetric lattice structures or interfacialsymmetry-breaking heterostructures. Here, we report the emergence of a Bloch-type skyrmion state in the frustrated centrosymmetric triangular-lattice magnet Gd2PdSi3. We identified the field-induced skyrmion phase via a giant topological Hall response, which is further corroborated by the observation of in-plane spin modulation probed by resonant x-ray scattering. Our results exemplify a new gold mine of magnetic frustration for producing topological spin textures endowed with emergent electrodynamics in centrosymmetric magnets.

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Quantum transport of quasi–two-dimensional Dirac fermions is largely controlled by magnetic order in a layered magnet.