"Interplay of nanoscale strain and smectic order in kagome superconductors"
Exotic quantum solids can host electronic states that spontaneously break rotational symmetry of the electronic structure, such as electronic nematic phases and unidirectional charge density waves (CDWs). When electrons couple to the lattice, uniaxial strain can be used to anchor and control this electronic directionality. Here we reveal an unusual impact of strain on unidirectional “smectic” CDW orders in kagome superconductors AV3Sb5 using spectroscopic-imaging scanning tunneling microscopy. We discover local decoupling between the smectic electronic director axis and the direction of anisotropic strain. While the two can be generally aligned along the same direction in regions of small CDW gap, the tendency for alignment decreases in regions where CDW gap is the largest. This in turn suggests nanoscale variations in smectic susceptibility, which we attribute to a combination of local strain and electron correlation strength. Overall, we observe an unusually high decoupling rate between the smectic electronic director of the 3-state Potts order and anisotropic strain, revealing weak smecto-elastic coupling in the CDW phase of kagome superconductors.