Twist-angle dependence of electron correlations in moiré graphene bilayers
arXiv:1905.01887 · doi:10.1103/PhysRevB.100.121106
Abstract
Motivated by the recent observation of correlated insulator states and unconventional superconductivity in twisted bilayer graphene, we study the dependence of electron correlations on the twist angle and reveal the existence of strong correlations over a narrow range of twist-angles near the magic angle. Specifically, we determine the on-site and extended Hubbard parameters of the low-energy Wannier states using an atomistic quantum-mechanical approach. The ratio of the on-site Hubbard parameter and the width of the flat bands, which is an indicator of the strength of electron correlations, depends sensitively on the screening by the semiconducting substrate and the metallic gates. Including the effect of long-ranged Coulomb interactions significantly reduces electron correlations and explains the experimentally observed sensitivity of strong correlation phenomena on twist angle.
17 pages, 6 figures
References in corpus (7)
- The electronic properties of graphene
- Flat Bands in Slightly Twisted Bilayer Graphene
- Numerical studies of confined states in rotated bilayers of graphene
- An exact continuum model for low-energy electronic states of twisted bilayer graphene
- Continuum models for twisted bilayer graphene: the effects of lattice deformation and hopping parameter
- Structure of twisted and buckled bilayer graphene
- Antiferromagnetism in the Hubbard Model on the Bernal-stacked Honeycomb Bilayer
Cited by in corpus (28)
- Untying the insulating and superconducting orders in magic-angle graphene
- Cascade of electronic transitions in magic-angle twisted bilayer graphene
- Superconductivity without insulating states in twisted bilayer graphene stabilized by monolayer WSe
- Anomalous Hall metal and fractional Chern insulator in twisted transition metal dichalcogenides
- Origin and Evolution of Ultraflatbands in Twisted Bilayer Transition Metal Dichalcogenides: Realization of Triangular Quantum Dot Array
- Derivation of Wannier orbitals and minimal-basis tight-binding hamiltonians for twisted bilayer graphene: a first-principles approach
- Attractive electron-electron interactions from internal screening in magic angle twisted bilayer graphene
- Effect of bilayer stacking on the atomic and electronic structure of twisted double bilayer graphene
- Importance of long-ranged electron-electron interactions for the magnetic phase diagram of twisted bilayer graphene
- Critical role of device geometry for the phase diagram of twisted bilayer graphene
- Band Renormalization, Quarter Metals, and Chiral Superconductivity in Rhombohedral Tetralayer Graphene
- 3/2 magic-angle quantization rule of flat bands in twisted bilayer graphene and relationship with the Quantum Hall effect
- Constrained Random Phase Approximation of the effective Coulomb interaction in lattice models of twisted bilayer graphene
- Why the first magic-angle is different from others in twisted graphene bilayers: interlayer currents, kinetic and confinement energy and wavefunction localization
- Spontaneous Valley Spirals in Magnetically Encapsulated Twisted Bilayer Graphene
- Flat bands, electron interactions and magnetic order in magic-angle mono-trilayer graphene
- Coulomb Engineering of two-dimensional Mott materials
- Doping fingerprints of spin and lattice fluctuations in moiré superlattice systems
- Plasmonic Quantum Dots in Twisted Bilayer Graphene
- Chiral SO(4) spin-valley density wave and degenerate topological superconductivity in magic-angle-twisted bilayer-graphene
- Charge order and Mott insulating ground states in small-angle twisted bilayer graphene
- Charge and spin correlations in insulating and incoherent metal states of twisted bilayer graphene
- Short vs. long range exchange interactions in twisted bilayer graphene
- Magnetoplasmons in magic-angle twisted bilayer graphene
- Construction of low-energy symmetric Hamiltonians and Hubbard parameters for twisted multilayer systems using ab-initio input
- Electronic structure and transport in materials with flat bands: 2D materials and quasicrystals
- Median-point approximation and its application for the study of fermionic systems
- Magnetic Ordering in Moiré Graphene Multilayers from a Continuum Hartree+U Approach