Enhanced superconductivity close to a non-magnetic quantum critical point in electron-doped strontium titanate.

ABSTRACT: Studies on quantum critical points (QCP) have focused on magnetic QCPs to date. Remarkable phenomena such as superconductivity due to avoided criticality have been discovered, but we focus here on the non-magnetic counterpart, i.e., the superconductivity of SrTiO₃ regarded as being close to a ferroelectric QCP. Here we prepare high-quality Sr_1-xLa_xTi(¹⁶O_1-z¹⁸O_z)₃ single crystals without localisation at low temperatures, which allow us to systematically investigate the La substitution of Sr as an alternative to introducing oxygen vacancies. Analysis of our data based on a theoretical model predicts an appearance of the ferroelectric QCP around 3 × 10¹⁸ cm^-3. Because of the QCP, the

SUBMITTER: Tomioka Y 

PROVIDER: S-EPMC6374393 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature