  The magnetic skyrmions generated in a centrosymmetric crystal were recently
first discovered in Gd2PdSi3. In light of this, we observe the electronic
structure by angle-resolved photoemission spectroscopy (ARPES) and unveil its
direct relationship with the magnetism in this compound. The Fermi surface and
band dispersions are demonstrated to have a good agreement with the density
functional theory (DFT) calculations carried out with careful consideration of
the crystal superstructure. Most importantly, we find that the
three-dimensional Fermi surface has extended nesting which matches well the
q-vector of the magnetic order detected by recent scattering measurements. The
consistency we find among ARPES, DFT, and the scattering measurements suggests
the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction involving itinerant
electrons to be the formation mechanism of skyrmions in Gd2PdSi3.
