Tuning of superconductivity in Kagome metal AV₃Sb₅ (A = K, Rb, Cs) by compressive and tensile biaxial strain

AV₃Sb₅ (A = K, Rb, Cs) are recently discovered Kagome metals with an interesting interplay between superconductivity and charge-density-wave orders. In this presentation, I will show our results on the biaxial strain tuning of the AV₃Sb₅. Relying on the differential thermal expansion between the sample and different types of substrates, we successfully apply both compressive and tensile strain on AV₃Sb_5, and the superconducting phase transition temperature (T_c) is suppressed with compressive strain, while it is enhanced under a tensile strain. For instance, in RbV₃Sb₅ T_c can be enhanced by ~ 30% (0.82 K to 1.08 K) compared with the free-standing value when the RbV₃Sb₅ single crystal is placed on sapphire. In addition to the zero-field T_c, I will also present the field-temperature phase diagram and comment on the superconducting anisotropy. Our work shows that biaxial strain is an effective way to tune the superconducting properties of Kagome superconductors.