Electronic correlations in the normal state of the kagome superconductor KV3Sb5

Abstract

Recently, intensive studies have revealed fascinating physics, such as charge density wave and superconducting states, in the newly synthesized kagome-lattice materials AV3Sb5 (A=K, Rb, Cs). Despite the rapid progress, fundamental aspects such as the magnetic properties and electronic correlations in these materials have not been clearly understood yet. Here, based on density functional theory plus single-site dynamical mean-field theory calculations, we investigate the correlated electronic structure and magnetic properties of the KV3Sb5 family materials in the normal state. We show that these materials are good metals with weak local correlations. The obtained Pauli-like paramagnetism and the absence of local moments are consistent with a recent experiment. We reveal that the band crossings around the Fermi level form three groups of nodal lines protected by the spacetime inversion symmetry, each carrying a quantized π Berry phase. Our result suggests that the local correlation strength in these materials appears to be too weak to generate unconventional superconductivity, and nonlocal electronic correlation might be crucial in this kagome system.

Source-reported materials — not catalogue approval

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