Tuning the ground state of iron based superconductors by uniaxial strain*

Uniaxial strain has emerged as a prominent tuning tool for accessing previously unexplored regions of phase space in quantum materials. In particular, in iron-based superconductors the susceptibility of the electronic structure to applied uniaxial strain has opened up new avenues to create and control varied quantum phases.
In our research programme, we have explored the magnetic and superconducting phase diagram under uniaxial strain along [110] crystallographic direction of FeTe. FeTe is an ‘11’ non-superconducting parent compound with double stripe AFM order ground state having (π,0) propagation vector contrary to the more typical (π, π) order. We combined low-temperature magnetoresistivity measurements in a force cell and direct spectroscopic imaging with STM, which revealed (π, π) ordering under uniaxial strain. In light of our results on this and other compounds we discuss the possibility of stabilising new order both on the surface and in bulk under experimentally accessible strains in iron-based superconductor.