Impact Of The Orbital Current Order On The Superconducting Properties Of The Kagome Superconductors

Recently,the observation of chiral charge density wave（CCDW）order in the vanadium-based kagome superconductor AV₃Sb₅has garnered extensive attention from researchers.CCDW is a charge order with chiral and flux characteristics,caused by pe-riodic charge density waves formed by electrons in the lattice,together with the accom-panying orbital current,that breaks the time-reversal symmetry of the system.CCDW is believed to have significant impacts on the normal and superconducting states of vanadium-based kagome superconductors,such as inducing quantum anomalous Hall effect and edge states.Despite extensive research on the charge density wave order and superconducting properties of vanadium-based kagome superconductors,the un-derstanding of its unconventional superconducting properties,superconducting pairing mechanism,and the impact of CCDW on superconducting properties are still unclear and even controversial.Further exploration and research are still necessary.Inspired by recent experimental evidence of CCDW in vanadium-based kagome superconductors,we theoretically investigated the impact of CCDW on the normal and superconducting state properties.Our study found that CCDW opens a gap on a portion of the Fermi surface but preserves spectral weight at the midpoint between M and its adjacent M points.The momentum dependence of the gap along the Fermi surface is consistent with recent experimental observations.More importantly,conventional nodeless superconducting pairing with U-shaped density of states is transformed into nodal pairing with V-shaped density of states due to the modulation of the gap on the Fermi surface by CCDW.As a result,the density of states remains non-zero near zero energy,and its shape changes from U-shaped to V-shaped.These findings are highly consistent with recent experimental observations and offer a promising explanation for a range of seemingly conflicting experimental phenomena.