Speaker
Dr
Adrien Stucky
(University of Geneva, Departement of Quantum Matter pHysics)
Description
The strength of the electron-phonon coupling in the superconducting mechanism of n-doped STO is still under debate. Interestingly, it has been proven that SrTiO$_3$ becomes ferroelectric at low temperature when $^{16}$O atoms are substituted by their isotope $^{16}$O. Using DC resistivity and AC susceptibly measurements we have determined the effect of $^{18}$O/$^{16}$O isotope substitution on T$_c$ and H$_c$. We observed a factor 1.5 increase of T$_c$ and H$_{c2}$ at any doping levels. This isotope effect is opposite to BCS theory, but anticipated by models of polaronic band narrowing, as well as proximity to a ferroelectric quantum critical point.
Authors
Dr
Adrien Stucky
(University of Geneva, Departement of Quantum Matter pHysics)
Mrs
Dorota Pulmannovà
(University of Geneva, Departement of Quantum Matter pHysics)
Co-authors
Dr
Gernot Werner Schereer
(University of Geneva, Departement of Quantum Matter Physics)
Dr
Zhi Ren
(University of Geneva, Departement of Quantum Matter Physics)
Prof.
Didier Jaccard
(University of Geneva, Departement of Quantum Matter Physics)
Dr
Jean-Marie Poumirol
(University of Geneva, Departement of Quantum Matter Physics)
Dr
Céline Barreteau
(University of Geneva, Departement of Quantum Matter Physics)
Dr
Enrico Giannini
(University of Geneva, Departement of Quantum Matter Physics)
Prof.
Dirk van der Marel
(University of Geneva, Departement of Quantum Matter Physics)
