10/2019

Investigating the Pairing Mechanism across 1D Nanocrosses at LaAlO₃/SrTiO₃ Interface

The unconventional nature of superconductivity at the LaAlO₃/SrTiO₃ interface has intrigued researchers for several decades. Recent realization of non-superconducting paired electron states [1] has further added richness to this superconducting complex-oxide interface. However, experimental insights into the nature of electron pairing in LaAlO₃/SrTiO₃ heterostructures remains elusive. Recent experimental results suggest that the pairing mechanism at the interface may be related to the boundaries of these naturally formed X, Y and Z ferroelastic domains in SrTiO₃ [2].

We investigate the relation between the pairing mechanism in 1D nanostructures at the LaAlO₃/SrTiO₃ interface and the corresponding ferroelastic domain configuration. We write 1D, cross-shaped electron waveguides, nanocrosses, at the LaAlO₃/SrTiO₃ interface using conductive atomic force microscope (c-AFM) lithography. The c-AFM writing and device geometry together defines Z-X and Z-Y domain boundaries across the nanocross at low temperatures. Longitudinal and Hall magnetotransport measurements across the nanocross provide deep insights into our understanding of the pairing mechanism at the LaAlO₃/SrTiO₃ interface and the role of ferroelastic domains of SrTiO₃ on it.

[1] Nature 521, 196 (2015)

[2] Physical review letters 120 (14), 147001 (2018)

Publication:

1.      A. Nethwewala, H. Lee, M. Briggeman, Y. Tang, J. Li, J. Lee, C.-B. Eom, P. R. Irvin and J. Levy, Nanoscale Horizons, 2019, DOI: 10.1039/c9nh00188c.