The interplay between charge density waves (CDWs) and high-temperature superconductivity is currently under intense investigation. Experimental research on this issue is difficult because CDW formation in bulk copper-oxides is strongly influenced by random disorder, and a long-range-ordered CDW state in high magnetic fields is difficult to access with spectroscopic and diffraction probes. Here we use resonant x-ray scattering in zero magnetic field to show that interfaces with the metallic ferromagnet La2/3Ca1/3MnO3 greatly enhance CDW formation in the optimally doped high-temperature superconductor YBa2Cu3O6+δ (δ∼1), and that this effect persists over several tens of nm. The wavevector of the incommensurate CDW serves as an internal calibration standard of the charge carrier concentration, which allows us to rule out any significant influence of oxygen non-stoichiometry, and to attribute the observed phenomenon to a genuine electronic proximity effect. Long-range proximity effects induced by heterointerfaces thus offer a powerful method to stabilize the charge density wave state in the cuprates, and more generally, to manipulate the interplay between different collective phenomena in metal oxides.
@article{arxiv.1606.05531,
title = {Long-range charge density wave proximity effect at cuprate-manganate interfaces},
author = {A. Frano and S. Blanco-Canosa and E. Schierle and Y. Lu and M. Wu and M. Bluschke and M. Minola and G. Christiani and H. U. Habermeier and G. Logvenov and Y. Wang and P. A. van Aken and E. Benckiser and E. Weschke and M. Le Tacon and B. Keimer},
journal= {arXiv preprint arXiv:1606.05531},
year = {2016}
}