Evidence for Fermi surface reconstruction in compressed CsV3Sb5 with stripe order

The observation of stripelike charge density wave (CDW) order in pressurized CsV₃Sb₅ implies unique electronic correlation effects in this kagome superconductor. However, it remains unknown how the stripe order affects the band structure of CsV₃Sb₅ at high pressure. Here, we perform anisotropic resistivity ratio and thermopower measurements under pressure and find that their behavior significantly changes when the system enters the stripelike CDW state. More intriguingly, the anisotropic resistivity ratio suddenly decreases and at the same time the thermopower shows a humplike behavior below TCDW in the stripelike CDW phase. Our results indicate the enhancement of the interlayer coupling in the stripelike CDW phase, which couples to the band structure below TCDW. These findings provide an alternative experimental framework for understanding the underlying physics behind the pressure-induced stripelike CDW order in kagome superconductors.