Suppression of T_C in an underdoped iron-based superconductor through uniaxial strain

The iron-based superconductors generically have been shown to host the electronic nematic phase which competes with superconductivity. Previous work has also shown that anisotropic strain is particularly well suited as a tunable, symmetry breaking field that can couple to the nematic order parameter. In this work, we present electrical transport, magnetic susceptibility, and single crystal x-ray diffraction measurements demonstrating that the superconducting transition in an underdoped iron-based superconductor is efficiently tuned towards zero temperature through the application of large, uniaxial strain that enhances the orthorhobmic distortion. This demonstrates that application of mechanical strain is a novel external parameter that is able to tune a superconductor to metal transition in a three-dimensional system.