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Strong enhancement of s-wave superconductivity near a quantum critical point of Ca3Ir4Sn13

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Biswas P. K., Guguchia Z., Khasanov R., Chinotti M., Li L., Wang Kefeng, Petrovic C., Morenzoni E.,
Project Interplay between the superconductivity and magnetism in cuprate and Fe-based superconductors
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Original article (peer-reviewed)

Volume (Issue) 92(19)
Page(s) 195122
Title of proceedings PHYSICAL REVIEW B
DOI 10.1103/physrevb.92.195122


We report microscopic studies by muon spin rotation/relaxation as a function of pressure of the Ca3Ir4Sn13 and Sr3Ir4Sn13 cubic compounds, which are members of the (Ca1-xSrx)(3)Ir4Sn13 system displaying superconductivity and a structural phase transition associated with the formation of a charge density wave (CDW). We find a strong enhancement of the superfluid density and a dramatic increase of the pairing strength above a pressure of approximate to 1.6 GPa, giving direct evidence of the presence of a quantum critical point separating a superconducting phase coexisting with CDW from a pure superconducting phase. The superconducting order parameter in both phases has the same s-wave symmetry. In spite of the conventional phonon-mediated BCS character of the weakly correlated (Ca1-xSrx)(3)Ir4Sn13 system, the dependence of the effective superfluid density on the critical temperature puts this compound in the ``Uemura{''} plot close to unconventional superconductors. This system exemplifies that conventional BCS superconductors in the presence of competing orders or multiband structure can also display characteristics of unconventional superconductors.}