Fate of Berezinskii-Kosterlitz-Thouless Paired Phase in Coupled $XY$ Models

Abstract

Intriguing phases may emerge when two-dimensional systems are coupled in a bilayer configuration. In particular, a Berezinskii-Kosterlitz-Thouless (BKT) paired superfluid phase was predicted and claimed to be numerically observed in a coupled $XY$ model with ferromagnetic interlayer interactions, as reported in [\href{https://doi.org/10.1103/PhysRevLett.123.100601}{Phys. Rev. Lett. 123, 100601 (2019)}]. However, both our Monte Carlo simulations and analytical analysis show that this model does not exhibit a BKT paired phase. We then propose a new model incorporating paired-phase gradient interlayer interactions to realize the BKT paired phase. Moreover, we observe that the anomalous magnetic dimension varies along the phase transition line between the disordered normal phase and the BKT paired phase. This finding requires an understanding beyond the conventional phase transition theory.

References in corpus (24)

• Graphene Bilayers with a Twist
• Quantum anomalous Hall effect from intertwined moiré bands
• Localization and delocalization of light in photonic moire lattices
• Tools for quantum simulation with ultracold atoms in optical lattices
• Dipolar physics: A review of experiments with magnetic quantum gases
• Bilayer $t$-$J$-$J_{\perp }$ Model and Magnetically Mediated Pairing in the Pressurized Nickelate La${}_3$Ni${}_2$O${}_7$
• Atomic Bose-Einstein condensate in a twisted-bilayer optical lattice
• Quartic metal: Spontaneous breaking of time-reversal symmetry due to four-fermion correlations in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• Valley-Polarized Quantum Anomalous Hall State in Moiré MoTe${}_2$/WSe${}_2$ Heterobilayers
• Large-scale Monte Carlo simulation of two-dimensional classical XY model using multiple GPUs
• Single-particle vs. pair superfluidity in a bilayer system of dipolar bosons
• Charge-4e and charge-6e flux quantization and higher charge superconductivity in kagome superconductor ring devices
• Exciton Proliferation and Fate of the Topological Mott Insulator in a Twisted Bilayer Graphene Lattice Model
• Superconductivity and bosonic fluid emerging from Moiré flat bands
• Phase coherence of pairs of Cooper pairs as quasi-long-range order of half-vortex pairs in a two-dimensional bilayer system
• Calorimetric evidence for two phase transitions in Ba${}_{1-\mathrm{x}}$K${}_{\mathrm{x}}$Fe${}_2$As${}_2$ with fermion pairing and quadrupling states
• Prediction of time-reversal-symmetry breaking fermionic quadrupling condensate in twisted bilayer graphene
• Emergent Potts Order in a Coupled Hexatic-Nematic XY model
• Observation of counterflow superfluidity in a two-component Mott insulator
• High-order Time-Reversal Symmetry Breaking Normal State
• Reentrance of Berezinskii-Kosterlitz-Thouless-like transitions in three-state Potts antiferromagnetic thin film
• Magnetic Bloch States at Integer Flux Quanta Induced by Super-moiré Potential in Graphene Aligned with Twisted Boron Nitride
• Observation of a Bilayer Superfluid with Interlayer Coherence
• Helicity modulus in the bilayer XY model by worm algorithm