At the interface between electron and hole-doped cuprates

Abstract

CoverThe cover shows a false color scanning electron microscope image (250 µm wide from front to back) of an eerie landscape of cones and ridges that forms on the surface of YBa 2 Cu 3 O 7-x during pulsed laser ablation. With each pulse, the surface cracks and ripples due to large thermal stresses. The cones form as yttrium collects in the crests of the ripples, causing them to harden and protect the material underneath. The resulting landscape bears a striking resemblance to rock formations called Hoodoos, which form via a similar mechanism, but on a much larger scale.

Strain accommodation through facet matching in La1.85Sr0.15CuO4/Nd1.85Ce0.15CuO4 ramp-edge junctions

“…electronic transport measurements, described elsewhere. 6,7 Here, we focus on the structural characterization of the interface between NCCO and LSCO in the ramp area of the junctions. We employ two different techniques to probe the interface: scanning nano-focused X-ray diffraction (nXRD) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM).…”

“…The layer composition is verified by electron diffraction and energy dispersive X-ray spectroscopy (EDX), discussed in more detail elsewhere. 6,7 The exact tilting of the LSCO lattice is determined by looking at the Fourier transforms of the NCCO and the LSCO lattices and is found to be 3.3…”

“…The LSCO top electrode is deposited after an extra in situ cleaning step of hard and soft argon ion milling. The final devices are structured for electronic transport measurements, described elsewhere 6,7 . Here, we focus on the structural characterization of the interface between NCCO and LSCO in the ramp area of the junctions.…”

“…The NCCO and LSCO layers can be identified, as well as a tilting of the LSCO lattice, indicated with yellow lines. The layer composition is verified by electron diffraction and energy dispersive X-ray spectroscopy (EDX), discussed in more detail elsewhere 6,7 . The exact tilting of the LSCO lattice is determined by looking at the Fourier transforms of the NCCO and the LSCO lattices and is found to be 3.3 • on the central part of the ramp.…”

“…Conversely, it also means that the LSCO/NCCO ramp-edge junctions have a crystalline grain boundary contact at the interface. Firstly, this is important for the electronic measurements discussed elsewhere 6,7 , but secondly, it also means that a rampedge structure can potentially be used to tailor specific, artificial grain boundaries in piezoelectric materials like BiFeO 3 to enhance their piezoelectric properties. A periodic mesa structure in SrTiO 3 with ramps on both sides could yield an artificial realization of the mixed phase state as observed by Zeches et al 21 .…”