Title: Pair Density Wave as a Primary Order in a Two-Orbital Kagome Lattice

Speaker: Prof. Qiang-Hua Wang (Nanjing University)

Time: 10:00, Jan. 6 (Tuesday) 2026

Place: Rm M830, IOP-CAS

Abstract
Pair density wave (PDW) is a superconducting state with non-zerocenter-of-mass momentum Cooper pairing in the absence of externalmagnetic field. Recent experiments show signature of such an intriguingstate. However, theoretical models supporting such a state are rare, sinceusual zero-momentum pairing or spin/charge order might overwhelm thePDW state. Here, by state-of-art functional renormalization group, weshow that a PDW state can be realized, out of competing orders, in a two-orbital kagome lattice under fairly realistic material conditions: finite-sizedFermi pockets and moderate local Coulomb interactions. The model enjoysthe following key ingredients that make the PDW favorable: 1) The Blochstates on the Fermi surfaces are strongly sublattice and orbital polarized onthe Fermi pockets, so that pairing between unequal sublattices, triggeredby the correlation effect, is enforced to pick up a finite total momentum,while local onsite pairing is forbidden by the repulsive Coulomb interaction;2) The Fermi surfaces avoid the van Hove singularities which would alsoenhance the particle-hole channels. The degenerage PDW states at threeM-momenta on the Brillouine zone boundaries could linearly combine intochiral PDW states that are topologically nontrivial. We propose this modelcan be realized in some p-or d-orbital kagome materials such as CsCrgSbs,and may also be simulated by cold atoms.