Effect of uniaxial strain on superconductivity in K(Nb_xTa_{1-x})O_3

The pairing mechanism of superconductivity in oxide-based heterostructures has long been debated. In KTaO₃ (KTO), quantum fluctuations are thought to inhibit the onset of long-range ferroelectric order [1,2], which may play a role in its superconducting pairing mechanism. Previous experiments have demonstrated that KTO can be driven into a ferroelectric phase through applied stress [3] or Nb doping [4]. Recent observations have shown that doping KTO with Nb can significantly increase its superconducting transition temperature (Tc). Here we investigate the effect of strain on Nb-doped KTO using low-temperature transport measurements under dynamic uniaxial stress. Our results will be compared with strain experiments on undoped KTO and LaAlO₃/SrTiO₃.

[1] Rowley, S. E. et al. arXiv:1801.08121 [cond-mat.supr-con].

[2] Rowley, S. E. et al. Nat. Phys. 10, 367 (2014).

[3] Uwe, H. et al. Solid State Commun. 13, 737 (1973).

[4] Maglione, M. et al. Europhys. Lett. 4, 631 (1987).