Mixed pairing symmetry in kappa-(BEDT-TTF)(2)X organic superconductors from ultrasonic velocity measurements
|Title||Mixed pairing symmetry in kappa-(BEDT-TTF)(2)X organic superconductors from ultrasonic velocity measurements|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Dion M, Fournier D, Poirier M, Truong KD, Tremblay A-MS|
|Journal||Physical Review B|
Discontinuities in elastic constants are detected at the superconducting transition of layered organic conductors kappa-(BEDT-TTF)(2)X by longitudinal and transverse ultrasonic velocity measurements. Symmetry arguments show that discontinuities in shear elastic constants can be explained in the orthorhombic compound only if the superconducting order parameter has a mixed character that can be of two types, either A(1g)+B-1g or B-2g+B-3g in the classification of irreducible representations of the orthorhombic point group D-2h. Consistency with other measurements suggests that the A(1g)+B-1g(d(xy)+d(z(x+y))) possibility is realized. Such clear symmetry-imposed signatures of mixed order parameters have not been observed in other superconducting compounds.