Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in $B{i}_{2}S{r}_{2}CaC{u}_2{O}_{8+\delta }$ monolayer

Abstract

Monolayers of a prototypical cuprate high transition-temperature ($T_C$) superconductor $B{i}_{2}S{r}_{2}CaC{u}_2{O}_{8+\delta }$ (Bi2212) was recently found to show $T_C$ and other electronic properties similar to those of the bulk. The robustness of superconductivity in an ideal two-dimensional (2D) system was an intriguing fact that defied the Mermin-Wagner theorem. Here, we took advantage of the high sensitivity of scanning SQUID susceptometry to image the phase stiffness throughout the phase transition of Bi2212 in the 2D limit. We found susceptibility oscillated with flux between diamagnetism and paramagnetism in a Fraunhofer-like pattern up till $T_C$. The temperature and sample size-dependence of the modulation period agreed well with our Coulomb gas analogy of a finite 2D system based on Berezinskii-Kosterlitz-Thouless (BKT) transition. In the multilayers, the susceptibility oscillation differed in a small temperature regime below $T_C$ in consistent with a dimensional-crossover led by interlayer coupling. Serving as strong evidence of BKT transition in the bulk, there appeared a sharp superfluid density jump at zero-field and paramagnetism at small fields just below $T_C$. These results unified the phase transitions from the monolayer Bi2212 to the bulk as BKT transition with finite interlayer coupling. This elucidating picture favored the pre-formed pairs scenario for the underdoped cuprates regardless of lattice dimensionality.

References in corpus (10)

• Theory of Intertwined Orders in High Temperature Superconductors
• Lattice symmetry breaking in cuprate superconductors: Stripes, nematics, and superconductivity
• Quantum critical behaviour in the superfluid density of strongly underdoped ultrathin cuprate films
• High-T_c superconductivity in ultrathin Bi_2Sr_2CaCu_2O_8+x down to halfunit-cell thickness by protection with graphene
• Fluctuation Superconductivity in Mesoscopic Aluminum Rings
• Doping dependence of the vortex-core energy in bilayer films of cuprates
• 3D nano-bridge-based SQUID susceptometers for scanning magnetic imaging of quantum materials
• Fluctuation diamagnetism in high temperature superconductors
• The uniformly frustrated two-dimensional XY model in the limit of weak frustration
• Effect of Disorder on the Superfluid Transition in Two-Dimensional Systems

Cited by in corpus (2)

• Flux focusing with a superconducting nano-needle for scanning SQUID susceptometry
• Extracting intrinsic superconducting properties in intercalated layered superconductors using an extended 2D Tinkham model