Effect of uniaxial strain on KTaO3 superconductivity*

The pairing mechanism of superconductivity in oxide-based heterostructures has been a topic of enduring debate. Among the numerous proposed mechanisms, those connected to structural transitions have gained prominence. Oxides like undoped SrTiO3 and KTaO3 exhibit quantum paraelectric behavior, which can be manipulated towards ferroelectricity through various means such as electric fields, oxygen substitution, hydrostatic pressure, and strain. Several theoretical studies [1][2][3] propose a potential link between superconductivity and ferroelectricity in these emerging ferroelectrics [1]. To explore the potential correlation, we conduct transport experiments at millikelvin temperatures under applied uniaxial stress at the LaAlO3/KTaO3 interface. We compare our findings with strain-dependent studies of SrTiO3-based devices.

 

[1]  S. E. Rowley, C. Enderlein, J. F. de Oliveira, D. A. Tompsett, E. Baggio Saitovitch, S. S. Saxena, and G. G. Lonzarich, Superconductivity in the vicinity of a ferroelectric quantum phase transition, (2018), arXiv:1801.08121 [cond-mat.supr-con].

[2] J. M. Edge, Y. Kedem, U. Aschauer, N. A. Spaldin, and A. V. Balatsky, Quantum critical origin of the superconducting dome in SrTiO3, Phys. Rev. Lett. 115, 247002 (2015).

[3] S. E. Rowley, L. J. Spalek, R. P. Smith, M. P. M. Dean, M. Itoh, J. F. Scott, G. G. Lonzarich, and S. S. Saxena, Ferroelectric quantum criticality, Nat. Phys. 10, 367 (2014).