Superconductivity and charge carrier localization in ultrathin $\mathbf{L}{\mathbf{a}}_{1.85}\mathbf{S}{\mathbf{r}}_{0.15}\mathbf{Cu}{\mathbf{O}}_4/\mathbf{L}{\mathbf{a}}_2\mathbf{Cu}{\mathbf{O}}_4$ bilayers

Abstract

$\mathrm{L}{\mathrm{a}}_{1.85}\mathrm{S}{\mathrm{r}}_{0.15}\mathrm{Cu}{\mathrm{O}}_4$/$\mathrm{L}{\mathrm{a}}_2\mathrm{Cu}{\mathrm{O}}_4$ (LSCO15/LCO) bilayers with a precisely controlled thickness of N unit cells (UCs) of the former and M UCs of the latter ([LSCO15\_N/LCO\_M]) were grown on (001)-oriented {\slao} (SLAO) substrates with pulsed laser deposition (PLD). X-ray diffraction and reciprocal space map (RSM) studies confirmed the epitaxial growth of the bilayers and showed that a [LSCO15\_2/LCO\_2] bilayer is fully strained, whereas a [LSCO15\_2/LCO\_7] bilayer is already partially relaxed. The \textit{in situ} monitoring of the growth with reflection high energy electron diffraction (RHEED) revealed that the gas environment during deposition has a surprisingly strong effect on the growth mode and thus on the amount of disorder in the first UC of LSCO15 (or the first two monolayers of LSCO15 containing one $\mathrm{Cu}{\mathrm{O}}_2$ plane each). For samples grown in pure ${\mathrm{N}}_2\mathrm{O}$ gas (growth type-B), the first LSCO15 UC next to the SLAO substrate is strongly disordered. This disorder is strongly reduced if the growth is performed in a mixture of ${\mathrm{N}}_2\mathrm{O}$ and ${\mathrm{O}}_2$ gas (growth type-A). Electric transport measurements confirmed that the first UC of LSCO15 next to the SLAO substrate is highly resistive and shows no sign of superconductivity for growth type-B, whereas it is superconducting for growth type-A. Furthermore, we found, rather surprisingly, that the conductivity of the LSCO15 UC next to the LCO capping layer strongly depends on the thickness of the latter. A LCO capping layer with 7~UCs leads to a strong localization of the charge carriers in the adjacent LSCO15 UC and suppresses superconductivity. The magneto-transport data suggest a similarity with the case of weakly hole doped LSCO single crystals that are in a so-called {"{cluster-spin-glass state}"}

References in corpus (20)

• High-temperature interface superconductivity between metallic and insulating cuprates
• Electrical Resistivity Anisotropy from Self-Organized One-Dimensionality in High-Temperature Superconductors
• Localized Superconductivity in the Quantum-Critical Region of the Disorder-Driven Superconductor-Insulator Transition in TiN Thin Films
• Temporal correlations of superconductivity above the transition temperature in La${}_{2-x}$Sr${}_x$CuO${}_4$ probed by terahertz spectroscopy
• Spintronic oxides grown by laser-MBE
• Superconducting transition at 38 K in insulating-overdoped La2CuO4-La1.64Sr0.36CuO4 superlattices: Evidence for interface electronic redistribution from resonant soft x-ray scattering
• Magnetic order and superconductivity in LSCO: a review
• Temperature Evolution of the Pseudogap State in the Infra-Red Response of Underdoped La_(2-x)Sr_xCuO_4
• Universal transport in 2D granular superconductors
• Terahertz ellipsometry study of the soft mode behavior in ultrathin SrTiO3 films
• Pulsed laser deposition growth of heteroepitaxial YBa2Cu3O7/La0.67Ca0.33MnO3 superlattices on NdGaO3 and Sr0.7La0.3Al0.65Ta0.35O3 substrates
• Emergence of superconductivity from the dynamically heterogeneous insulating state in La_{2-x}Sr_{x}CuO_{4}
• Magnetic phase diagram of low-doped La{2-x}SrxCuO4 thin films studied by low-energy muon-spin rotation
• Superconducting Fluctuation investigated by THz Conductivity of La${}_{2-x}$Sr${}_x$CuO${}_4$ Thin Films
• Magnetism in the 2D Limit and Interface Superconductivity in Metal-Insulator La(2-x)Sr(x)CuO(4) Superlattices
• Spin-polarized quasiparticle injection effects in YBCO thin films
• Frustration of the interlayer coupling by mobile holes in La2-xSrxCuO4 (x<0.02)
• Structural, magnetic and superconducting properties of pulsed-laser-deposition-grown $\mathrm{L}{\mathrm{a}}_{1.85}\mathrm{S}{\mathrm{r}}_{0.15}\mathrm{Cu}{\mathrm{O}}_4/L{\mathrm{a}}_{2/3}\mathrm{C}{\mathrm{a}}_{1/3}\mathrm{Mn}{\mathrm{O}}_3$ superlattices on $(001)$-oriented $\mathrm{LaSrAl}{\mathrm{O}}_4$ substrates
• Growth of Single Unit-Cell Superconducting La${}_{2-x}$Sr${}_x$CuO${}_4$ Films
• Large Positive Magnetoresistance of the Lightly Doped La_{2}CuO_{4} Mott Insulator

Cited by in corpus (3)

• Emergence of high-temperature superconductivity at the interface of two Mott insulators
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