Enhanced superconductivity and ferroelectric quantum criticality in plastically deformed strontium titanate

Abstract

The properties of quantum materials are commonly tuned using experimental variables such as pressure, magnetic field and doping. Here we explore a different approach: irreversible, plastic deformation of single crystals. We show for the archetypal unconventional superconductor SrTiO3 that compressive plastic deformation induces lowdimensional superconductivity significantly above the superconducting transition temperature (Tc) of undeformed samples. We furthermore present evidence for unusual normal-state transport behaviour that suggests superconducting correlations at temperatures two orders of magnitude above the bulk Tc. The superconductivity enhancement is correlated with the appearance of structural features related to selforganized dislocation structures, as revealed by diffuse neutron and X-ray scattering.These results suggest that deformed SrTiO3 is a potential high-temperature superconductor, and push the limits of superconductivity in this low-density electronic system. More broadly, we demonstrate the promise of plastic deformation and dislocation engineering as tools to manipulate electronic properties of quantum materials.

Elucidating the Origins of a Range of Diverse Flexible Responses in Crystalline Coordination Polymers

“…On the other hand, a pronounced azimuthal elongation of Bragg peaks (known as asterisms) was observed at spot 1. Asterisms, typically noticed on plastically deformed metals or perovskite-type oxides (e.g., strontium titanate), are generally a result of tilts of mesoscopic, relatively defect-poor crystalline regions bounded by structural dislocations. The more pronounced the azimuthal elongation is, the larger the number of small crystalline domains, with the preserved unit cell of undeformed crystal, slightly tilted to each other.…”

Defect-induced electronic smectic state at the surface of nematic materials

“…The mechanism unveiled in this work for the emergence of a surface electronic smectic state above the onset of bulk electronic nematicity is rather general, as it relies solely on the existence of defects commonly observed at crystal surfaces. While here we focused on steps, other defects with nonzero dipolar elastic moments' are expected to promote a similar behavior, since they also generate algebraically-decaying strain fields that are poorly screened at the surface (for a specific example of point defects, see the SM) [61,62]. Our result unearths yet another aspect of the rich phenomenology of electronic nematicity caused by the coupling to the elastic degrees of freedom.…”

60 years of dislocations in ceramics: A conceptual framework for dislocation mechanics in ceramics

“…A core charge does not occur in metals due to their bond type and delocalized electrons. Strain field, charged core and compensating space charge can impact a multitude of functional properties 23,45 such as thermal conductivity, 16,20,[46][47][48] ionic and electronic conductivity, 24,[49][50][51][52][53][54][55][56] space charges (including Schottky barriers), 22,57 ferroelectric properties, [58][59][60][61] catalytic activtiy, 62 superconductivity 63,64 and optical properties. 17 This also includes the performance of cathode materials in batteries 21 and lithium metal plating behavior on solid electrolytes.…”