Isotope effect in superconducting n-doped SrTiO$_3$

• DOI: 10.48550/arxiv.1610.10045
• Publication Date: 2016-01-01
• Authors: A. Stucky; G. W. Scheerer; Zhi Ren; D. Jaccard; Jean‐Marie Poumirol; Céline Barreteau; E. Giannini; D. van der Marel
• Keywords: Kinetic isotope effect; Lattice vibration; Lattice (music)

We report the influence on superconducting critical temperature $T_c$ in doped SrTiO$_3$ of substitution natural $^{16}$O atoms by heavier isotope $^{18}$O. observe that for a wide range doping this causes strong ($\sim 50 \%$) enhancement $T_c$. Also magnetic field $H_{c2}$ is increased factor $\sim 2$. Such impact and $H_{c2}$, with sign opposite to conventional superconductors, unprecedented. The observed effect could be consequence coupling electrons lattice vibrations (phonons), notion which finds support numerous optical photo-emission studies. unusually large size supports recent model superconductivity these materials based ferroelectric soft modes SrTiO$_{3}$.