Welcome to the Superpuddles Lab
The Lab is part of the Institute of Metallic Materials, a department at the Leibniz Institute for Solid State Research in Dresden (IFW).
In our Lab we synthesize topological superconductors in complex quantum matter. Our main focus is to advance the tools for the synthesis, nanoscale imaging, and control of topological superconductors in complex quantum matter and the dynamic of steady states out-of-equilibrium. Our ultimate challenge is to realize specifically tailored topological superconducting properties in complex quantum matter that are robust up to room temperature. Although we are driven by curiosity, we keep an eye open for applications of our reasearch in solid state quantum technologies that need higher operation temperatures.
Highlights
Scale invariant pattern of oxygen rich puddles and superconductivity
The position dependence of the oxygen rich puddles for two typical samples obtained by following different annealing–quenching protocols, resulting in Tc = 40 K (a) and Tc = 16+32 K phases. Visual inspection of a and b shows that the spikes corresponding to ordered microdomains are more isolated for the more disordered sample with lower Tc than for the high-Tc sample, indicating that the nucleation and growth of oxygen rich puddles proceeds to smaller length scales for shorter annealing times.
Optimal inhomogeneity evolution of the lattice deformations (static incommensurate CDW) with the High-Tc superconductivity
X-ray microdiffraction results for the position dependence of the lattice deformed puddles (static incommensurate charge density waves puddles) in the High-Tc crystals with different critical temperature, Tc , 32, 34, and 37 K from A to C. The scanning XRD images show the better self organization of lattice deformed puddles (CDW), proceeding to the higher Tc.
X-ray photoinduced oxygen rich puddles ordering and restoration of superconductivity
The oxygen rich puddles are photo-switched in the same surface layer thickness of the sample. b,c show the (oxygen rich puddles) superlattice peak profiles along the in-plane k-direction (b) and the out-of-plane l-direction (c) as a function of the X-ray exposure time at constant X-ray photon flux ΦP(0.1 nm)=5×1014NP(0.1 nm) s−1 cm−2 and fixed temperature 250 K, starting from the quenched disordered i-O phase with suppressed satellite reflections. There is clear evidence for both a time threshold before the oxygen interstitials ordering process into oxgen rich puddles starts and also for the lack of saturation of the intensity growth after 14 h.
Spatial anti-correlation between oxygen-rich and lattice deformed (CDW) puddles
The lattice deformed puddles (CDW-rich puddles) (red) on the CuO2 planes and oxygen rich puddles (blue) on the HgOy layers. b, Surface plot of the difference map (see Methods) between the CDW-peak and Oi-streak intensity. The positive (green to red) values indicate the CDW-rich regions and the negative (green to blue) values correspond to Oi-rich regions. Scale bar, 5 µm. c, Scatter plot of Oi versus CDW intensity demonstrating the negative correlation between CDW-puddle and Oi-stripe populations. d, Segmentations of the difference map in b highlighting the network of CDW-rich domains (left panel) and Oi-rich regions (right panel). Scale bar, 10 µm. e, A schematic of the nanoscale texture formed by CDW-rich regions (red spots) and the ‘charge-Oi-rich’ region (light blue area), which define an interface space and loci of the superconductivity with a complex non-Euclidean geometry.
Dynamic phase transitions in mesoscopic proximity network of superconducting puddles
Representative dV/dI versus f = B/B0 curves at different bias currents. At low current bias (blue, orange, and yellow), dV/dI minima at f = , , , 1, , , , 2, , , , and 3 indicate formation of a vortex Mott insulator. Increasing current reverses minima into maxima (red and violet). Reversals manifesting the insulator-to-metal transition are highlighted by vertical arrows. (C) Ground-state energy Eg versus f obtained from the Harper equation. (D) Vortex configurations at rational frustrations f = 0, , , , and 1. Periodic arrays of vortices (yellow circles) are superimposed on the SEM subimages of the square array of Nb islands.
Enhancement of vortex contribution to the transport in atomically thin Bi2.1Sr1.9CaCu2.0O8+δ High-Tc Superconductors
The double sign change. (a) Temperature dependencies of Rxy(T) at fixed magnetic fields for the 2 unit cells thick device. Fits above (dash-dotted) and below (dashed lines) Tc are superimposed on experimental data (symbols). Inset: Superconducting gap extracted from fits. Tc is the temperature extracted from the analysis of Rxx(T) in the framework of superconducting fluctuations. (b) The Hall sign-reversal phase diagram. Shading shows Hall resistance Rxy(B,T) gor a 2 UC device with Tc = 81.5 K. The blue region shows the area of negative Hall resistance. Symbols show the locus Rxy = 0 for different thicknesses, and the lines are generated from fits to Rxy = 0. As thickness decreases, the Hall signreversed region becomes larger and vortex contribution stronger to the transport.