Coupled Cu and Mn charge and orbital orders in YBa2Cu3O7/Nd0.65(Ca1-ySry)0.35MnO3 multilayers

E Perret,C Monney,C Bernhard,M Minola,B Keimer,S Johnston,F Lyzwa,C Piamonteze,B P P Mallett,M Dantz,J Khmaladze,R Gaina,J Pelliciari,T Schmitt

doi:10.1038/s42005-018-0046-z

Abstract

The observation of a charge density wave in the underdoped cuprate high Tc superconductors (Cu-CDW) raised a debate about its relationship with superconductivity. In bulk YBa2Cu3O7−δ the Cu-CDW is incipient and mainly pinned by defects. Nevertheless, a large magnetic field can induce a true long-range Cu-CDW order as it suppresses superconductivity. An enhanced Cu-CDW order was also observed in YBa2Cu3O7/La2/3Ca1/3MnO3 multilayers. Here, we show that the magnitude of the Cu-CDW in YBa2Cu3O7−δ / Nd0.65(Ca1-ySry)0.35MnO3 multilayers can be varied by adjusting the strength of the manganite charge and orbital order via the Sr content (tolerance factor). Furthermore, we resolve the reconstruction of the crystal field levels of the interfacial Cu ions that are also affected by the manganite charge and orbital order. This tuneable interfacial coupling and Cu-CDW in YBa2Cu3O7−δ can be used for studying the relationship between the Cu-CDW and superconductivity and, possibly, for inducing new intertwined quantum states.

Highlights

The observation of a charge density wave in the underdoped cuprate high Tc superconductors (Cu-CDW) raised a debate about its relationship with superconductivity
We provide evidence that the manganite charge and orbital order (Mn–COO) affects the orbital reconstruction of the interfacial Cu ions and causes a lateral modulation that can act as a template for the Cu-CDW
This setup has provided in the past the first, direct evidence for a Cu-CDW in underdoped YBCO with Q∥ = (1/3,0) or (0,1/3) (r.l.u.)[2]

Summary

Introduction

The observation of a charge density wave in the underdoped cuprate high Tc superconductors (Cu-CDW) raised a debate about its relationship with superconductivity. We resolve the reconstruction of the crystal field levels of the interfacial Cu ions that are affected by the manganite charge and orbital order This tuneable interfacial coupling and Cu-CDW in YBa2Cu3O7−δ can be used for studying the relationship between the Cu-CDW and superconductivity and, possibly, for inducing new intertwined quantum states. For A = La, an itinerant ferromagnetic ground state prevails in large parts of the phase diagram (0.2 ≤ y ≤ 0.45), where the so-called colossal magnetoresistance (CMR) effect arises from the competition of the doubleexchange interaction with Jahn-Teller-type lattice distortions[11] The former is determined by the kinetic energy or the bandwidth of the charge carriers, which can be modified via tÂhpe ffiMffi n–O bondÃangle or the tolerance factor t 1⁄4 ðrA þ rOÞ= 2ðrMn þ rOÞ , where rA, rO, and rMn are the radii of the A-site cation, oxygen and manganese ions, respectively. Even though the oxygen ions seem to be involved in this order[12,13,14,15], we denote these electronic orderings in the following (for simplicity) as a manganite charge and orbital order (Mn–COO)

Methods

Results

Conclusion