Related papers: Anomalous Drag in Double Bilayer Graphene Quantum-…
We present a symmetry-based analysis of competition between different gapped states that have been proposed in bilayer graphene (BLG), which are all degenerate on a mean field level. We classify the states in terms of a hidden SU(4)…
We show through both theoretical arguments and numerical calculations that graphene discerns an unconventional sequence of quantized Hall conductivity, when subject to both magnetic fields (B) and strain. The latter produces time-reversal…
The electronic Raman scattering of bulk graphite at zero magnetic field reveals a structureless signal characteristic of a metal. For T<~100 K and B > 2 T, several peaks at energies scaling linearly with magnetic field were observed and…
Bilayer graphene in a magnetic field supports eight zero-energy Landau levels, which, as a tunable band gap develops, split into two nearly-degenerate quartets separated by the band gap. A close look is made into the properties of such an…
We investigate low-temperature magneto-transport in recently developed, high-quality multi-terminal suspended bilayer graphene devices, enabling the independent measurement of the longitudinal and transverse resistance. We observe clear…
The quantum anomalous Hall effect can occur in single and few layer graphene systems that have both exchange fields and spin-orbit coupling. In this paper, we present a study of the quantum anomalous Hall effect in single-layer and gated…
Electron-electron interactions play an important role in graphene and related systems and can induce exotic quantum states, especially in a stacked bilayer with a small twist angle. For bilayer graphene where the two layers are twisted by a…
Bilayer graphene, in the presence of a one-sided spin-orbit interaction (SOI) induced by a suitably chosen substrate, is predicted to exhibit unconventional Quantum Hall states. The new states arise due to strong SOI-induced splittings of…
We report on magneto-transport studies of dual-gated, Bernal-stacked trilayer graphene (TLG) encapsulated in boron nitride crystals. We observe a quantum Hall effect staircase which indicates a complete lifting of the twelve-fold degeneracy…
Spin splitting of the energy spectrum of single-layer graphene on Au/Ni(111) substrate has been recently reported. I show that eigenstates of spin-orbit coupled graphene are polarized in-plane and perpendicular to electron momentum $\bf k$;…
The minimum of 4-terminal conductance occurring at its charge neutral point has proven to be a robust empirical feature of graphene, persisting with changes to temperature, applied magnetic field, substrate, and layer thickness, though the…
In a graphene bilayer with Bernal stacking both $n=0$ and $n=1$ orbital Landau levels have zero kinetic energy. An electronic state in the N=0 Landau level consequently has three quantum numbers in addition to its guiding center label: its…
A possible realization of Hall conductivity, quantized at odd integer factors of $e^2/h$ for graphene's honeycomb lattice is proposed. I argue that, in the presence of \emph{uniform} real and pseudo-magnetic fields, the valley degeneracy…
In a quantizing magnetic field, the chiral two-dimensional electron gas in Landau level $N=0$ of bilayer graphene goes through a series of phase transitions at integer filling factors $\nu \in \left[ -3,3\right] $ when the strength of an…
Magic-angle twisted bilayer graphene (tBLG) has been studied extensively owing to its wealth of symmetry-broken phases, correlated Chern insulators, orbital magnetism, and superconductivity. In particular, the anomalous Hall effect (AHE)…
We analyze the quantum Hall effect in single layer graphene with bilayer stripe defects. Such defects are often encountered at steps in the substrate of graphene grown on silicon carbide. We show that AB or AA stacked bilayer stripes result…
Coulomb drag resulting from interlayer electron-electron scattering in double layer 2D electron systems at high magnetic field has been measured. Within the lowest Landau level the observed drag resistance exceeds its zero magnetic value by…
The zero-energy Landau level of bilayer graphene is shown to be anomalously sharp (delta-function like) against bond disorder as long as the disorder is correlated over a few lattice constants.The robustness of the zero-mode anomaly can be…
Near a magic twist angle, bilayer graphene transforms from a weakly correlated Fermi liquid to a strongly correlated two-dimensional electron system with properties that are extraordinarily sensitive to carrier density and to controllable…
We present a framework for understanding the recently observed cascade transitions and the Landau level degeneracies at every integer filling of twisted bilayer graphene. The Coulomb interaction projected onto narrow bands causes the…