Investigating the Interplay of Polar Nanodomains and Superconductivity in Doped Strontium Titanate through Transmission Electron Microscopy.

The simultaneous presence of itinerant carriers and polar crystal distortions poses a persistent challenge, especially in polar superconductors such as doped strontium titanate (SrTiO₃). This study employs scanning transmission electron microscopy (STEM) to investigate the interplay between ferroelectricity and superconductivity in SrTiO₃. Contrary to conventional models, the ferroelectric transition in strained, undoped SrTiO₃ exhibits pronounced order-disorder characteristics. Increasing carrier concentration disrupts polar nanodomains, with dopant atoms contributing to the suppression of the ferroelectric transition. The destruction of the global ferroelectric state correlates with the suppression of superconductivity in strained SrTiO₃ films, emphasizing the essential role of polar order. The length scale of polar order emerges as a crucial parameter controlling superconductivity in SrTiO₃, providing valuable insights into the competition between itinerant carriers and polar crystal distortions. [ABSTRACT FROM AUTHOR]