The locally noncentrosymmetric heavy fermion superconductor CeRh2As2 has attracted considerable interest recently due to its rich superconducting phases, accompanied by a quadrupole density wave and pronounced antiferromagnetic excitations. To understand the underlying physics, we performed a high-resolution angle-resolved photoemission study of this compound. Our results reveal the splittings of the conduction bands, which are directly related to the locally noncentrosymmetric structure, as well as a quasi-two-dimensional Fermi surface with strong 4f contributions, implying weak interlayer hopping. The Fermi surface is clearly nested by an in-plane vector q1 and can provide a natural explanation for the observed magnetic excitation at ({\pi}/a, {\pi}/a), as well as the concomitant quadrupole density wave. The experimental results are corroborated by dynamical mean-field theory calculations, which can well capture the lattice Kondo effect. Our study therefore provides important spectroscopic insight to understand the magnetic excitations and quadrupole order in CeRh2As2, as well as their connections with the peculiar superconductivity.
Comment: v1 submitted on Sep 13th 2023