Figure 2: Low magnetic field fan diagram.
From: Strong electronic interaction and multiple quantum Hall ferromagnetic phases in trilayer graphene
(a) Colour plot of Rxx as a function of Vbg and B up to 1.5 T. The LL crossings arising from ML bands and BL bands are clearly seen. Each parabola is formed by the repetitive crossings of a particular ML LL with other BL LLs. Crossing between any two LLs shows up as Rxx maxima in transport measurement due to high DOS at the crossing points. The overlaid magenta line shows a line slice at Vbg=50 V. (b) DOS corresponding to a. NM=1 labelled parabola refers to all the crossing points arising from the crossings of NM=1 LL with other BL LLs. Other labels have a similar meaning. NM=0 LL does not disperse with B, hence the crossings form a straight line parallel to B axis. Minimum B is taken as 0.5 T to keep finite number of LLs in the calculation. The horizontal axis is converted from charge density to an equivalent Vbg after normalizing it by the capacitance per unit area (Cbg) for the ease of comparison with experimental fan diagram. Cbg is determined from the high B quantum Hall data which matches well with the geometrical capacitance per unit area of 30 nm hBN and 300 nm SiO2: Cbg∼105 μFm−2.
