Interaction and coherence in 2D bilayers
arXiv:2312.10838 · doi:10.1103/PhysRevB.109.085129
Abstract
In bilayer systems, the additional layer pseudospin enables the emergence of interlayer coherence (IC), which is a direct consequence of the interlayer Coulomb interaction. This study presents a comprehensive HF investigation of IC in 2D bilayers, uncovering ground-state behaviors and temperature-dependent phase transitions that are distinct from single-layer 2DEG. This IC signals a spontaneous breaking of the U(1) symmetry in pseudospin. We explore the zero-temperature phase diagrams as a function of the electron density and interlayer separation within the HF formalism. We also calculate the critical temperature () of the interlayer coherence onset by self-consistently solving the HF gap-like equation. We contrast this IC phase in e-e bilayers with the closely related excitonic superfluid phase in e-h bilayers. Though both e-e and e-h bilayers spontaneously break the pseudospin U(1) symmetry, e-h bilayers produce BCS-BEC crossover intrinsic to the excitons acting as effective bosons or Cooper pairs, whereas the symmetry-broken phase in e-e bilayers is akin to the XY or easy-plane pseudospin ferromagnetism. Using the same system parameters and a similar theoretical framework, we find that of the interlayer coherent phase in e-e bilayers is about one-third of that in exciton condensates, suggesting a weaker IC in e-e bilayers. In addition, we examine the effect of a weak interlayer tunneling on the IC order parameter, drawing parallels with the influence of an effective in-plane magnetic field on the XY pseudospin ferromagnetism. Our findings provide a comparative theoretical framework that bridges the gap between the IC physics in e-e and e-h bilayers, contributing to a unified understanding of phase transitions in low-dimensional electron/hole systems and establishing in particular the same universality class for interlayer phase coherence in both e-e and e-h bilayers.
References in corpus (61)
- Observation of resonance condensation of fermionic atom pairs
- Condensation of Pairs of Fermionic Atoms Near a Feshbach Resonance
- Bose-Einstein Condensation of Excitons in Bilayer Electron Systems
- Experimental Study of the BEC-BCS Crossover Region in Lithium 6
- BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
- Spontaneous Inter-layer Coherence in Double-Layer Quantum-Hall Systems I: Charged Vortices and Kosterlitz-Thouless Phase Transitions
- Collective excitations of a degenerate gas at the BEC-BCS crossover
- Evidence for a Goldstone Mode in a Double Layer Quantum Hall System
- Exciton condensate in semiconductor quantum well structures.
- Counterflow measurements in strongly correlated GaAs hole bilayers: evidence for electron-hole pairing
- Vanishing Hall Resistance at High Magnetic Field in a Double Layer Two-Dimensional Electron System
- Quantum Ferromagnetism and Phase Transitions in Double-Layer Quantum Hall Systems
- Excitonic superfluid phase in Double Bilayer Graphene
- BCS-BEC Crossover and the Unitary Fermi Gas
- Quantum Hall Drag of Exciton Superfluid in Graphene
- Exciton Condensation and Perfect Coulomb Drag
- Observation of a Linearly Dispersing Collective Mode in a Quantum Hall Ferromagnet
- Observation of Quantized Hall Drag in a Strongly Correlated Bilayer Electron System
- Gate-Tuned Spontaneous Exciton Insulator in Double-Quantum Wells
- Observation of pair condensation in the quasi-2D BEC-BCS crossover
- Coulomb Drag in the Exciton Regime in Electron-Hole Bilayers
- Strongly enhanced tunneling at total charge neutrality in double bilayer graphene-WSe heterostructures
- Anomalous Coulomb drag in electron-hole bilayers
- Gate-controlled BCS-BEC crossover in a two-dimensional superconductor
- Activated Transport in the individual Layers that form the =1 Exciton Condensate
- Gauge Fields and Pairing in Double-Layer Composite Fermion Metals
- Double-layer quantum Hall antiferromagnetism at filling fraction nu=2/(odd integer)
- Spin-Excitation-Instability-Induced Quantum Phase Transitions in Double-Layer Quantum Hall Systems
- Crossover between Strongly-coupled and Weakly-coupled Exciton Superfluids
- Canted antiferromagnetic and spin singlet quantum Hall states in double-layer systems
- Plasmons in coupled bilayer structures
- Interlayer tunneling in double-layer quantum Hall pseudo-ferromagnets
- Excitonic instability and electric-field-induced phase transition towards a two dimensional exciton condensate
- Spontaneous Interlayer Coherence in Double-Layer Quantum Hall Systems: Symmetry Breaking Interactions, In-Plane Fields and Phase Solitons
- Wigner supersolid of excitons in electron-hole bilayers
- Bi-layer Paired Quantum Hall States and Coulomb Drag
- Broken Symmetry Ground States in ν=2 Bilayer Quantum Hall Systems
- Canted antiferromagnetic phase in a double quantum well in a tilted quantizing magnetic field
- Trial Wavefunctions for ν= 1/2 + 1/2 Quantum Hall Bilayers
- Undoped Electron-Hole Bilayers in a GaAs/AlGaAs Double Quantum Well
- Evidence from quantum Monte Carlo of large gap superfluidity and BCS-BEC crossover in double electron-hole layers
- Exchange Instabilities in Semiconductor Double Quantum Well Systems
- High temperature pairing in a strongly interacting two-dimensional Fermi gas
- Exciton Transport and Andreev Reflection in a Bilayer Quantum Hall System
- Spin Bose Glass Phase in Bilayer Quantum Hall Systems at
- Bilayer Quantum Hall Systems at Filling Factor ν=2: An Exact Diagonalisation Study
- Interlayer Transport in Bilayer Quantum Hall Systems
- Dissipationless transport in low density bilayer systems
- Precursors to Exciton Condensation in Quantum Hall Bilayers
- Double-Layer Systems at Zero Magnetic Field
- -wave paired composite-fermion electron-hole trial state for quantum Hall bilayers with
- Composite Fermion Pairing in Bilayer Quantum Hall Systems
- Josephson-like tunnel resonance and large Coulomb drag in GaAs-based electron-hole bilayers
- Spin-Orbit Interactions in Bilayer Exciton-Condensate Ferromagnets
- Tunneling between Dilute GaAs Hole Layers
- Spin-squeezed Ground States in the Bilayer Quantum Hall Ferromagnet
- Spin mapping, phase diagram, and collective modes in double layer quantum Hall systems at
- Many-body multipole index and bulk-boundary correspondence
- Spin symmetry breaking in bilayer quantum Hall systems
- Pseudospin Transfer Torques in Semiconductor Electron Bilayers
- Quantum Hall Bilayer as Pseudospin Magnet