Integer quantum Hall effect in graphene channel with p-n junction at domain wall in a strained ferroelectric film

We revealed that 180° domain walls in a strained ferroelectric film can induce p-n junctions in a graphene channel and lead to the nontrivial temperature and gate voltage dependences of the perpendicular modes of the integer quantum Hall effect (IQHE). In particular, the number of perpendicular modes v⊥, corresponding to the p-n junction across the graphene channel, varies with the gate voltage increase from small integers to higher non-integer numbers, e.g., v⊥ = 1.9, 2, …, 5.1, 6.875, …, 9.1, …, 23,…, 37.4, in the vicinity of the transition temperature from the ferroelectric to paraelectric phase. The non-integer numbers and their irregular sequence principally differ from the sequence of non-integer numbers ν = 3/2, 5/3, … reported earlier. The unusual v⊥-numbers originate from significantly different numbers of the edge modes, ν1 and ν2, corresponding to different concentrations of carriers in the left (n1) and right (n2) domains of the p-n junction boundary. The concentrations n1 and n2 are determine...