Electronic correlations in the normal state of the kagome superconductor KV3Sb5

Recently, intensive studies have revealed fascinating physics, such as charge\ndensity wave and superconducting states, in the newly synthesized\nkagome-lattice materials $A$V$_3$Sb$_5$ ($A$=K, Rb, Cs). Despite the rapid\nprogress, fundamental aspects like the magnetic properties and electronic\ncorrelations in these materials have not been clearly understood yet. Here,\nbased on the density functional theory plus the single-site dynamical\nmean-field theory calculations, we investigate the correlated electronic\nstructure and the magnetic properties of the KV$_3$Sb$_5$ family materials in\nthe normal state. We show that these materials are good metals with weak local\ncorrelations. The obtained Pauli-like paramagnetism and the absence of local\nmoments are consistent with recent experiment. We reveal that the band\ncrossings around the Fermi level form three groups of nodal lines protected by\nthe spacetime inversion symmetry, each carrying a quantized $\\pi$ Berry phase.\nOur result suggests that the local correlation strength in these materials\nappears to be too weak to generate unconventional superconductivity, and\nnon-local electronic correlation might be crucial in this kagome system.\n