5 research outputs found
Tuning topological superconductivity within the -- model of twisted bilayer cuprates
We carry out a theoretical study of unconventional superconductivity in
twisted bilayer cuprates as a function of electron density and layer twist
angle. The bilayer -- model is employed and analyzed within the
framework of a generalized variational wave function approach in the
statistically-consistent Gutzwiller formulation. The constructed phase diagram
encompasses both gapless -wave state (reflecting the pairing symmetry of
untwisted copper-oxides) and gapped phase that
breaks spontaneously time-reversal-symmetry (TRS) and is characterized by
nontrivial Chern number. We find that state occupies
a non-convex butterfly-shaped region in the doping vs. twist-angle plane, and
demonstrate the presence of previously unreported reentrant TRS-breaking phase
on the underdoped side of the phase diagram. This circumstance supports the
emergence of topological superconductivity for fine-tuned twist angles away
from . Our analysis of the microscopically derived Landau free energy
functional points toward sensitivity of the superconducting order parameter to
small perturbations close to the topological state boundary