Strain-stabilized superconductivity

Superconductivity is among the most fascinating and well-studied quantum states of matter. Despite over 100 years of research, a detailed understanding of how features of the normal-state electronic structure determine superconducting properties has remained elusive. For instance, the ability to deterministically enhance the superconducting transition temperature by design, rather than by serendipity, has been a long sought-after goal in condensed matter physics and materials science, but achieving this objective may require new tools, techniques and approaches. Here, we report the transmutation of a normal metal into a superconductor through the application of epitaxial strain. We demonstrate that synthesizing RuO2 thin films on (110)-oriented TiO2 substrates enhances the density of states near the Fermi level, which stabilizes superconductivity under strain, and suggests that a promising strategy to create new transition-metal superconductors is to apply judiciously chosen anisotropic strains that redistribute carriers within the low-energy manifold of d orbitals. Epitaxial strain is a promising control knob to modulate Tc to enhance superconductivity. Here, the authors show that a metallic oxide RuO2 can be turned superconducting through application of epitaxial strain in thin films grown on a (110)-oriented TiO2 substrate.

Automated summary

The study successfully transformed a normal metal into a superconductor through the application of epitaxial strain, demonstrating the enhancement of superconducting properties by synthesizing RuO2 thin films on TiO2 substrates. The promising strategy of creating new transition-metal superconductors by redistributing carriers within d orbitals using carefully chosen anisotropic strains was discussed.