Аннотация:The quantum Hall effect near the charge neutrality point in bilayer graphene is investigated in high magnetic fields of up to 35 T using electronic transport measurements.In the high-field regime, the eightfold degeneracy in the zero-energy Landau level is completely lifted, exhibiting new quantum Hall states corresponding to filling factors ¼ 0, 1, 2, and 3. Measurements of the activation energy gaps for the ¼ 2 and 3 filling factors in tilted magnetic fields exhibit no appreciable dependence on the in-plane magnetic field, suggesting that these Landau level splittings are independent of spin.In addition, measurements taken at the ¼ 0 charge neutral point show that, similar to single layer graphene, the bilayer becomes insulating at high fields.
