Landau level of fragile topology

Strained bilayer graphene: Band structure topology and Landau level spectrum

We show that topology of the low-energy band structure in bilayer graphene critically depends on mechanical deformations of the crystal which may easily develop in suspended graphene flakes. We describe the Lifshitz transition that takes place in strained bilayers upon splitting the parabolic bands at intermediate energies into several Dirac cones at the energy scale of a few meV. Then, we show...

Landau Level Mixing and Solenoidal Terms in Lowest Landau Level Currents

We calculate the lowest Landau level (LLL) current by working in the full Hilbert space of a two dimensional electron system in a magnetic field and keeping all the non-vanishing terms in the high field limit. The answer a) is not represented by a simple LLL operator and b) differs from the current operator, recently derived by Martinez and Stone in a field theoretic LLL formalism, by solenoida...

DETERMINATION OF LANDAU LEVEL LIFETIMES IN n

Electrostatics of inter-Landau-level diodes.

We present exact solution of an electrostatic problem in terms of the potential distribution and density profile of an incompletely depleted two-dimensional electron gas in a heterostructure covered by a half-infinite gate. Using this solution, we calculate configurations of compressible and incompressible (insulating) strips that are formed in the presence of a quantizing magnetic field. We di...

Theory of the half-filled Landau level.

A recent theory of a compressible Fermi-liquid like state at Landau level filling factors ν = 1/q or 1 − 1/q, q even, is reviewed, with emphasis on the basic physical concepts.